Category: thiazole

Synthesis and bio-activity evaluation of tetraphenyl(phenylamino) methylene bisphosphonates as antioxidant agents and as potent inhibitors of osteoclasts in vitro was written by Balakrishna, A.;Reddy, M. Veera Narayana;Rao, P. Visweswara;Kumar, M. Anil;Kumar, B. Siva;Nayak, S. K.;Reddy, C. Suresh. And the article was included in European Journal of Medicinal Chemistry in 2011.Quality Control of 2-Methylthiazol-5-amine This article mentions the following:

A new series of tetra-Ph bisphosphonates have been elegantly synthesized by one-pot method and were characterized by elemental anal., FTIR, ¹H, ¹³C, ³¹P NMR, mass spectra and evaluated for their in vitro anti-bone resorptive activity by inhibiting growth of osteoclasts. Two bisphosphonates showed marked inhibition ratio (8 μM and 10 μM) and emerged as lead compounds All compounds were tested for their antioxidant (DPPH scavenging, reducing power and inhibition of lipid peroxidation). They exhibited potent in vitro antioxidant activity dose-dependently. In the experiment, the researchers used many compounds, for example, 2-Methylthiazol-5-amine (cas: 89281-44-7Quality Control of 2-Methylthiazol-5-amine).

2-Methylthiazol-5-amine (cas: 89281-44-7) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1).Various laboratory methods exist for the organic synthesis of thiazoles. For example, 2,4-dimethylthiazole is synthesized from thioacetamide and chloroacetone.Quality Control of 2-Methylthiazol-5-amine

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Synthesis of 4- and 5-arylthiazolinethiones as inhibitors of indoleamine 2,3-dioxygenase was written by Balti, Monaem;Plas, Aurelie;Meinguet, Celine;Haufroid, Marie;Themans, Quentin;Efrit, Mohamed Lotfi;Wouters, Johan;Lanners, Steve. And the article was included in Bioorganic & Medicinal Chemistry Letters in 2017.Quality Control of 2-Chloro-5-phenylthiazole This article mentions the following:

Docking studies of 4-phenylthiazolinethione on human IDO1 suggest complexation of the heme iron by the exocyclic sulfur atom further reinforced by hydrophobic interactions of the Ph ring within pocket A of the enzyme. On this basis, chem. modifications were proposed to increase inhibitory activity. Synthetic routes had to be adapted and optimized to yield the desired substituted 4- and 5-arylthiazolinethiones I (X = 2-OCH₃, 3-F, 4-CN, etc.) and II (X = H, 2-OCH₃, 3-Br, etc.). Their biol. evaluation shows that 5-aryl regioisomers are systematically less potent than the corresponding 4-aryl analogs. Substitution on the Ph ring does not significantly increase inhibition potency, except for 4-Br and 4-Cl derivatives In the experiment, the researchers used many compounds, for example, 2-Chloro-5-phenylthiazole (cas: 329794-40-3Quality Control of 2-Chloro-5-phenylthiazole).

2-Chloro-5-phenylthiazole (cas: 329794-40-3) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). Various laboratory methods exist for the organic synthesis of thiazoles. Prominent is the Hantzsch thiazole synthesis is a reaction between haloketones and thioamides.Quality Control of 2-Chloro-5-phenylthiazole

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Programmed synthesis of arylthiazoles through sequential C-H couplings was written by Tani, Satoshi;Uehara, Takahiro N.;Yamaguchi, Junichiro;Itami, Kenichiro. And the article was included in Chemical Science in 2014.Computed Properties of C9H7NS This article mentions the following:

A programmed synthesis of arylthiazoles (2-aryl, 4-aryl, 5-aryl, 2,4-diaryl, 2,5-diaryl, 4,5-diaryl, and 2,4,5-triaryl) via palladium or nickel catalyzed sequential C-H couplings of unfunctionalized thiazole using eleven distinct synthetic routes was discussed. This methodol. led to the synthesis of over 150 arylthiazoles including fatostatin (SREBP inhibitor). In the experiment, the researchers used many compounds, for example, 5-Phenylthiazole (cas: 1826-13-7Computed Properties of C9H7NS).

5-Phenylthiazole (cas: 1826-13-7) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). The nitrogen in thiazole is sp2 hybridized and the lone pair of electrons localized on the nitrogen is less reactive due to increased aromatic character and decreased basicity. It is protonated and alkylated/acylated at nitrogen forming hydrochloride and quaternary thiazolium salt.Computed Properties of C9H7NS

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Palladium-catalyzed arylation of azole compounds with aryl halides in the presence of alkali metal carbonates and the use of copper iodide in the reaction was written by Pivsa-Art, Sommai;Satoh, Tetsuya;Kawamura, Yoshiki;Miura, Masahiro;Nomura, Masakatsu. And the article was included in Bulletin of the Chemical Society of Japan in 1998.Related Products of 1826-13-7 This article mentions the following:

The reactions of iodobenzene with azole compounds, 1,2-disubstituted imidazoles and 2-substituted oxazoles and thiazoles, were examined in the presence of catalytic amounts of Pd(OAc)₂ and PPh₃ in DMF using alkali metal carbonates as bases. It was found that the coupling products, 5-arylazoles, e.g., I (Ar = Ph, 1-naphthyl, 2-thienyl, etc.), could be selectively produced in good yields by using Cs₂CO₃. In the case that their 2-position is unsubstituted, the site could also be arylated. In reactions using bromobenzene in place of iodobenzene, K₂CO₃ was also as effective as Cs₂CO₃. The addition of a stoichiometric amount of CuI appeared to specifically promote the reactions of thiazoles as well as those of thiophene derivatives The reactions of 2-unsubstituted azole compounds with aryl iodides could be mediated by CuI to some extent without using the palladium species to give 2-arylazoles. In the experiment, the researchers used many compounds, for example, 5-Phenylthiazole (cas: 1826-13-7Related Products of 1826-13-7).

5-Phenylthiazole (cas: 1826-13-7) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). Various laboratory methods exist for the organic synthesis of thiazoles. Prominent is the Hantzsch thiazole synthesis is a reaction between haloketones and thioamides.Related Products of 1826-13-7

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Thiazoles. XI. The preparation of 2-amino-5-(phenylazo)thiazoles and the reductive scission of 2,2′-azothiazoles and 2-(phenylazo)thiazoles with phenylhydrazine was written by Beyer, Hans;Wolter, Gerhard. And the article was included in Chemische Berichte in 1952.Product Details of 6318-74-7 This article mentions the following:

A diazonium solution from 9.3 g. PhNH₂ buffered with AcONa added at 0° to 11.4 g. 2-amino-4-methylthiazole (I) gives 90.6% 2-amino-4-methyl-5-(phenylazo)thiazole (II), p-RC₆H₄N:N.C:CR’.N:C(NH₂).S (IIa, R = H, R’ = Me), orange needles, m. 184° (di-Ac derivative, prepared by heating 1.09 g. II with 3 cc. Ac₂O 1 h. on a water bath, fine yellow needles, m. 254-5°). 5-p-Tolylazo homolog (IIa, R = R’ = Me), 90.5%, long dark red columns from AcOEt-Me₂CO, m. 189-90°, or rhombic sepia leaflets from EtOH, m. 190-1° (di-Ac derivative, yellow needles, m. 251°); 5-p-nitrophenyl analog (IIa, R = NO₂, R’ = Me), 93.5%, fine dull red needles, m. 192° (di-Ac derivative, dark red leaflets, m. 206°). Coupling the diazonium compound from 17.2 g. p-H₂NC₆H₄SO₂NH₂ (III) with I gives 75% p-(2-amino-4-methyl-5-thiazolylazo)benzenesulfonamide (IIa R = SO₂NH₂, R’ = Me), m. 202° (di-Ac derivative, cubelike orange-yellow crystals, m. 223°). Coupling the diazonium salt from 9.3 g. PhNH₂ with 17.6 g. 2-amino-4-phenylthiazole gives 87.8% 2-amino-4-phenyl-5-(phenylazo)thiazole (IIa, R = H, R’ = Ph), fine felted cinnabar needles, m. 195° (di-Ac derivative, felted yellow needles, m. 214°); 5-p-tolylazo homolog (IIa, R = Me, R’ = Ph), 71.4%, fine felted red-orange needles, m. 200° (di-Ac derivative, long felted yellow needles, m. 217°); 5-p-nitrophenyl analog (IIa, R = NO₂, R’ = Ph), 90.8%, fine moss-green needles, m. 254° (Ac derivative, shiny dark green crystals, m. 293°); p-(2-amino-4-phenyl-5-thiazolylazo)benzenesulfonamide (IIa R = SO₂NH₂, R’ = Ph) 75%, bright red needles with a green surface sheen, m. 255° (di-Ac derivative, small cinnabar-red needles, m. 293°). Coupling the diazonium salt from 10.7 g. p-toluidine with 10 g. 2-aminothiazole (IV) gives 72% 2-amino-5-(p-tolylazo)thiazole (IIa, R = Me, R’ = H), small fine red needles, sintering 180°, m. 205° (di-Ac derivative, dark brown powder, m. 243°); coupling the diazonium salt from 17.2 g. III with 10 g. IV gives 75% p-(2-amino-5-thiazolylazo)benzene sulfonamide (IIa, R = SO₂NH₂, R’ = H), microcrystalline brown-yellow powder, m. 223° (di-Ac derivative, yellow-brown amorphous powder, m. 235°). Azothiazoles are reductively split by PhNHNH₂ to the corresponding NH₂ compounds Heating 3.7 g. di-Et 2,2′-azobis(4-methyl-5-thiazolecarboxylate) and 10.8 g. PhNHNH₂ (V) slowly to 180° and keeping the mixture 5 min. at 180° and overnight at 20° give 78% Et 2-amino-4-methyl-5-thiazolecarboxylate, needles, m. 175-6°. Similarly, Et 2-phenylazo-4-methyl-5-thiazolecarboxylate and V give 90% of the 2-phenylhydrazino analog, rhombic leaflets, m. 194°, which, on further heating with V at 200° gives 72% 2-amino analog; in the same way, 2-phenylazo-4,5-diphenylthiazole gives the 2-amino compound, m. 186°. Heating 2,2′-azobis(4-phenylthiazole) or 2-phenylazo-4-phenylthiazole with V at 180° gives the corresponding hydrazo compounds which, on further heating at 220°, give 18 and 14% 2-amino-4-phenylthiazole, m. 147°. In the experiment, the researchers used many compounds, for example, 4,5-Diphenylthiazol-2-amine (cas: 6318-74-7Product Details of 6318-74-7).

4,5-Diphenylthiazol-2-amine (cas: 6318-74-7) belongs to thiazole derivatives. Thiazole rings are planar and aromatic. Thiazoles are characterized by larger pi-electron delocalization than the corresponding oxazoles and have therefore greater aromaticity. The pyridine-type nitrogen in the thiazole ring deactivates the ring for electrophilic substitution reactions, which is further reduced in acid due to protonation of the thiazole ring.Product Details of 6318-74-7

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Microwave-Accelerated Solvent- and Catalyst-Free Synthesis of 4-Aminoaryl/alkyl-7-chloroquinolines and 2-Aminoaryl/alkylbenzothiazoles was written by Motiwala, Hashim F.;Kumar, Raj;Chakraborti, Asit K.. And the article was included in Australian Journal of Chemistry in 2007.Safety of N-Phenylbenzo[d]thiazol-2-amine This article mentions the following:

An efficient synthesis of 4-aminoaryl/alkyl-7-chloroquinolines, e.g., I (R = H, Me, MeO, F, Cl, Br, OH, Ac, CO₂Me or NO₂), and 2-aminoaryl/alkylbenzothiazoles has been developed by microwave-accelerated regioselective aromatic nucleophilic substitution of 4,7-dichloroquinoline and 2-chlorobenzothiazole with aromatic and aliphatic amines under solvent-free conditions in the absence of any added protic or Lewis acid catalyst. Chemoselective reaction with the amino group in preference to the phenolic hydroxy group was observed Thus, the treatment of 4,7-dichloroquinoline (1 equivalent) with a mixture of aniline (2 equivalent) and phenol (2 equivalent) afforded exclusive formation of 4-aminophenyl-7-chloroquinoline. When 4,7-dichloroquinoline (1 equivalent) was sep. treated with 2-aminophenol (2 equivalent) and 4-aminophenol (2 equivalent), 4-(2′-hydroxyphenyl)-7-chloroquinoline and 4-(4′-hydroxyphenyl)-7-chloroquinoline, resp., were formed. In the experiment, the researchers used many compounds, for example, N-Phenylbenzo[d]thiazol-2-amine (cas: 1843-21-6Safety of N-Phenylbenzo[d]thiazol-2-amine).

N-Phenylbenzo[d]thiazol-2-amine (cas: 1843-21-6) belongs to thiazole derivatives. The thiazole ring has been identified as a central feature of numerous natural products, perhaps the most famous example of which is epothilone. Electrophilic attack at nitrogen depends on the presence of electron density at nitrogen as well as the position and nature of substituent linked to the thiazole ring.Safety of N-Phenylbenzo[d]thiazol-2-amine

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Direct amination of derivatives of benzothiazole was written by Vel’tman, R. P.. And the article was included in Zhurnal Obshchei Khimii in 1956.Application In Synthesis of Benzothiazole-5-carboxylic acid This article mentions the following:

Heating 6.4 g. 2-bromo-5-nitroaniline and 65 ml. 85% HCO₂H on steam bath 3 hrs. gave 89% 1-formylamino-2-bromo-5-nitrobenzene, m. 202-3° (from EtOH); with Na₂S₂ this gave 5-nitrobenzothiazole (cf. Fries and Wolter, C.A. 31, 1405¹). This reduced with SnCl₂-HCl to 5-aminobenzothiazole-H₂O, 60%, m. 76°. Oxidation of 5-methylbenzothiazole with KMnO₄ gave 5-carboxybenzothiazole, m. 261-2° (from H₂O); Et ester, m. 106-8° (from aqueous EtOH). The 5-substituted benzothiazoles were refluxed with equimolar amounts of NH₂OH.HCl and aqueous NaOH for 0.5-4 hrs. (the NO₂ derivative failed to react after a prolonged period). The usual treatment yielded the following products: 2-amino-5-methylbenzothiazole, m. 171-2°, 68%, from 5-methylbenzothiazole; 2,5-diaminobenzothiazole, m. 175°, 72%, from 5-aminobenzothiazole; 2-amino-5-carboxybenzothiazole, decompose 300°, 64%, from 5-carboxybenzothiazole. The 5-carbethoxy derivative failed to react as did the NO₂ derivative 2-Amino-5-benzothiazolecarboxylic acid gave the Et ester, m. 200-1°. In the experiment, the researchers used many compounds, for example, Benzothiazole-5-carboxylic acid (cas: 68867-17-4Application In Synthesis of Benzothiazole-5-carboxylic acid).

Benzothiazole-5-carboxylic acid (cas: 68867-17-4) belongs to thiazole derivatives. The thiazole ring is notable as a component of the vitamin thiamine (B1). Electrophilic attack at nitrogen depends on the presence of electron density at nitrogen as well as the position and nature of substituent linked to the thiazole ring.Application In Synthesis of Benzothiazole-5-carboxylic acid

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Vinylation of Benzylic Amines via C-N Bond Functionalization of Benzylic Pyridinium Salts was written by Guan, Weiye;Liao, Jennie;Watson, Mary P.. And the article was included in Synthesis in 2018.Computed Properties of C4H6N2S This article mentions the following:

Cross-couplings of aralkyl pyridinium tetrafluoroborates and vinylboronic acids or esters was developed. Via aralkyl pyridinium intermediates, aralkyl amines were engaged in these cross-couplings through C-N bond functionalization. This method boasts mild reaction conditions and excellent tolerance for heteroaryl substituents and a range of functional groups. In the experiment, the researchers used many compounds, for example, Thiazol-2-ylmethanamine (cas: 55661-33-1Computed Properties of C4H6N2S).

Thiazol-2-ylmethanamine (cas: 55661-33-1) belongs to thiazole derivatives. Thiazoles frequently appear in peptide studies. Thiazoles can also be used as protected formyl groups, which can be released in later stages of complex natural product synthesis. There are numerous natural products that possess a thiazole ring with broad pharmacological activities. Thiamine, also known as vitamin B1, possesses a thiazole ring linked with 2-methylpyrimidine-4-amine as hydrochloride salt.Computed Properties of C4H6N2S

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Synthesis and biological evaluation of analogs of the anti-tumor alkaloid naamidine A was written by Aberle, Nicholas;Catimel, Jenny;Nice, Edouard C.;Watson, Keith G.. And the article was included in Bioorganic & Medicinal Chemistry Letters in 2007.Synthetic Route of C15H12N2S This article mentions the following:

A small series of analogs, such as I [R⁴ = CH₂C₆H₄-4-OMe, C₆H₄-4-Cl, Ph, R⁵ = CH₂C₆H₄-4-OH; R⁴ = R⁵ = C₆H₄-4-OMe, C₆H₄-4-OH, Ph] and II, of the alkaloid naamidine A was synthesized and tested in vitro for their ability to inhibit mitogenesis in BaF/ERX cells. Replacement of the imidazole core of naamidine A with a thiazole was found to have only a minor effect on potency, and the 4-methoxybenzyl substituent of the natural product was shown to be unnecessary for activity. In the experiment, the researchers used many compounds, for example, 4,5-Diphenylthiazol-2-amine (cas: 6318-74-7Synthetic Route of C15H12N2S).

4,5-Diphenylthiazol-2-amine (cas: 6318-74-7) belongs to thiazole derivatives. Thiazoles in peptides or their ability to bind proteins, DNA and RNA has led to many synthetic studies and new applications. The pyridine-type nitrogen in the thiazole ring deactivates the ring for electrophilic substitution reactions, which is further reduced in acid due to protonation of the thiazole ring.Synthetic Route of C15H12N2S

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica

Thiazolocyanines. XII. Polar substituents in thiazole rings of thiazolocyanines was written by Sych, E. D.;Umanskaya, L. P.. And the article was included in Zhurnal Obshchei Khimii in 1964.Electric Literature of C4H6N2S This article mentions the following:

Spectra of thiazolocyanines showed that the conjugation of electroneg. groups in the 5-position of the thiazole ring in thiazolocyanines with the rest of the mol. is developed more effectively than that of the electropos. groups in the 5-position or of electroneg. groups in the 4-position. Bromination of 2-methylthiazole in AcOH gave 2-methyl-5-bromothiazole (I); MeI adduct m. 243°; the Me tosylate (undescribed) was prepared from p-MeC₆H₄SO₃Me at 90°. Refluxing 2-mercapto-5-acetamidothiazole with MeI in EtOH for 10 min. gave 2-(methylthio)-5-acetamidothiazole (II) m. 144°; the methiodide was prepared conventionally. NCCH₂NH₂.H₂SO₄ treated with aqueous KOH, followed by MeCS₂K for 10 hrs., gave a low yield of 2-methyl-5-aminothiazole, m. 110°; Ac₂O gave the 5-acetamido analog, m. 144°; the Et tosylate was prepared conventionally. I heated for 10 min. at 160° with PhN:CHOEt (III) followed by 0.5 hr. at 140° gave 2-(2-anilinovinyl)-5-bromothiazole Me tosylate, which with I Et tosylate in Ac₂O-Et₃N-EtOH for 5 min. gave after addition of NaClO₄ bis[3-methyl-5-bromo-2-thiazole]trimethinecyanine perchlorate, m. 183-4°, λ_maximum 566 mμ. 2,4-Dimethyl-5-acetylthiazole-EtI and EtOCH:C(CO₂Et)₂ in EtOH-Et₃N for 0.5 hr. gave bis[3-ethyl-4-methyl-5-acetyl-2-thiazole]trimethinecyanine iodide, m. 240°, λ_maximum 598 mμ. I Me tosylate and 2-(methylthio)benzothiazole Et tosylate similarly gave after addition of KI, yellow [3-methyl-5-bromo-2-thiazole] – [3 – ethyl – 2 – benzothiazole]methinecyanine iodide, m. >320°, λ_maximum 423 mμ. II Et tosylate and 2-methylbenzothiazole Et tosylate similarly gave yellow [3-ethyl-5-acetamido-2-thiazole] – [3-ethyl- 2- benzothiazole]methinecyanine tosylate, m. 235°, λ_maximum 434 mμ. Similarly, quinaldine Et tosylate gave red [3-methyl-5-acetamido-2-thiazole] – [3-ethyl-2-quinoline]methinecyanine iodide, m. 282°, λ_maximum 489 mμ. 2-Methyl-5-aminothiazole-MeI and 2-(methylthio)benzothiazole Et tosylate rapidly gave orange [3-methyl-5-amino-2-thiazole]-[3-ethyl-2-benzothiazole]methinecyanine iodide, m. 245°, λ_maximum 457 mμ. 2-Methyl-thiazole Me tosylate and III at 160° gave 81% 2-(2-anilinovinyl)-thiazole Me tosylate, which was directly treated with 3-ethyl-rhodanine in Ac₂O-Et₃N-EtOH and gave in 1 hr. 3-ethyl-5-[(3-methyl-2-thiazolinylidene)ethylidene]thiazolidine-2-thion-4-one, m. 220-1°, λ_maximum 535 mμ. 2-(2-Anilinovinyl)-5-bromothiazole Me tosylate similarly gave blue 3-ethyl-5-[(3-methyl-5-bromo-2-thiazolinylidene)ethylidene] thiazolidine-2-thion-4-one, m. 168°, λ_maximum 537 mμ. 2-Methyl-5-carbethoxythiazole and HC(OEt)₃ refluxed in pyridine 40 min. and treated with KI gave violet bis-[3-ethyl-5-carbethoxy-2-thiazole]trimethinecyanine iodide, m. 134°, λ_maximum 583 mμ. Similarly, 2-methyl-4-carbethoxythiazole Et tosylate gave bis[3-ethyl-4-carbethoxy-2-thiazole]trimethinecyanine iodide, m. 173° λ_maximum 542 mμ. 2-Ethyl-5-carbethoxythiazole Et tosylate and 2-(methylthio)benzothiazole Et tosylate in EtOH-Et₃N gave after addition of KI yellow [3-ethyl-5-carbethoxy-2-thiazole]-[3-ethyl-2-benzothiazole]methinecyanine iodide, m. 202°, λ_maximum 428 mμ. Similarly, 2-methyl-5-carbomethoxythiazole Et tosylate gave [3-ethyl-5-carbomethoxy-2-thiazole]-[3-ethyl-2-benzothiazole]methinecyanine tosylate, m. 233°, λ_maximum 430 mμ. II Et tosylate and 3-ethylrhodanine refluxed 10 min. in pyridine gave orange 3-ethyl-5-[3-ethyl-5-acetamido-2-thiazo-linylidene]thiazolidine-2-thion-4-one, m. 234-5°, λ_maximum 443 mμ. I Et tosylate and p-Me₂NC₆H₄CHO refluxed in Ac₂O gave with KI gave violet 2-(p-dimethylaminostyryl)-5-bromothiazole-MeI, m. 238°, λ_maximum 510 mμ; similarly prepared was 78% violet 2-(p-dimethylaminostyryl)-6-bromobenzothiazole Et tosylate, m. 272°, λ_maximum 540 mμ. 2-Methyl-5-acetamidothiazole Et tosylate and HC(OEt)₃ heated in PhNO₂ and treated with NaClO₄ gave bis[3-ethyl-5-acetamido-2-thiazole]trimethinecyanine perchlorate, λ_maximum 576 mμ. Similarly was prepared rather unstable bis[3-methyl-5-amino-2-thiazole]trimethinecyanine tosylate, λ_maximum 580 and 530 mμ, which lost the longer wavelength maximum on standing. In the experiment, the researchers used many compounds, for example, 2-Methylthiazol-5-amine (cas: 89281-44-7Electric Literature of C4H6N2S).

2-Methylthiazol-5-amine (cas: 89281-44-7) belongs to thiazole derivatives. Thiazoles frequently appear in peptide studies. Thiazoles can also be used as protected formyl groups, which can be released in later stages of complex natural product synthesis. The pyridine-type nitrogen in the thiazole ring deactivates the ring for electrophilic substitution reactions, which is further reduced in acid due to protonation of the thiazole ring.Electric Literature of C4H6N2S

Referemce:
Thiazole | C3H3NS – PubChem,
Thiazole | chemical compound | Britannica