2- Alkylmercapto

Few representative dyes of cyanine base (Table 2114) resulting from the condensation of alkylmercapto indolenine on 2-methylthiazoliurn have been described. 

Substituted 5-hydroxythiazoles (267b), Rj = alkylmercapto, acyl-amino, and sec-amino, are prepared by cydization of N-thioacyl-amino acids (266) with phosphorus tribromide or acetic anhydride (Scheme 137) (317, 350). i en the cydization of 266, R2 = H, is carried out with acetic anhydride in the presence of benzaldehyde (317, 325) or ethylformate (317), the benzylidene (268), R2=Ph, Rj = SR or CH2Ph, or 4-ethoxymethylene (268), Rj = SR and R2 = OEt, derivative is obtained directly (Scheme 138). 

The reactivity of halogens in pyridazine N- oxides towards nucleophilic substitution is in the order 5 > 3 > 6 > 4. This is supported by kinetic studies of the reaction between the corresponding chloropyridazine 1-oxides and piperidine. In general, the chlorine atoms in pyridazine A-oxides undergo replacement with alkoxy, aryloxy, piperidino, hydrazino, azido, hydroxylamino, mercapto, alkylmercapto, methylsulfonyl and other groups. 

The preparation of W-alkyl derivatives of 6-benzyl-3,5-dioxo-l,2,4-triazine by hydrolysis of the corresponding alkylmercapto derivatives was systematically studied by Cattelain. The conversion to known alkyl derivatives of dioxotriazines was used to determine the structure of alkylated methylmercapto derivatives. As will be shown later (e.g., Section H,B,4,b) this procedure has a general preparative significance for 1-alkyl derivatives of 6-azauracil. ... 

Xanthogenhydrazides, RO-CS NHNH2, give 5-alkoxy-l,2,3,4-thiatriazoles on treatment with nitrous acid, and dithiocarbazinic esters, RS-CS-NHNH2, give 5-alkylmercapto-l,2,3,4-thiatriazoles. ... 

Oxidation of 2-mercapto-l,2,4-triazolo[l,5-c]pyrimidines (174) with chlorine or bromine in water (64BRP951652 65JCS3369), with hydrogen peroxide and chlorine (95MIP1), as well as with sodium chlorate in hydrochloric acid (94JMC2371) gave the corresponding 2-sulfonyl halide derivatives 175. Oxidation of the 2-alkylmercapto compounds 176 to the 2-alkylsufonyl derivatives 177 was made with ammonium peroxodisulfate and sulfuric acid... 

Imino-3p-nitrophenyl-4-phenyl-A4-selenazoiine, preparation, 229 2-Iminoseienazolidin-4-ones, benzoylation, on imino nitrogen, 270 preparation, 269 table of products, 263 2-Iminoseienazolines, prototropic equilibrium, U.V. spectra, 231 Indolenine. 2-alkylmercapto, in synthesis of monomethine cyanine bases,... 

As the thiocarbamate S-oxides behave similarly to those of the alkylmercapto-s -triazines in other respects, it would be of interest to investigate their reactivity to haemoglobin. 

Two general methods have been described for the synthesis of this new class of meso-ionic compounds (196). The most convenient method is by the treatment of 4-bromo-l,2,3-triazolium salts (197, X = Br) with sodium sulfide in dimethylformamide. Alternatively, N-methylation of the isomeric 4- or 5-alkylmercapto-1,2,3-triazoles 198 or 199 with methyl tosylate gave intermediate triazolium salts (197, X = SR, Y = Tos), which yielded meso-ionic l,2,3-triazole-4-thiones (196) by 5-dealkylation by heating with piperidine. 

Alkylmercapto-Gruppen am 1,2,4-Oxadiazol lassen sich mit Wasserstoffperoxid in Eisessig zu den Sulfoxiden oxidieren, wahrend mit waBriger Kaliumpermanganat-Losung die Sulfone entstehen175 z. B. ... 

Thiols and thiophenols generally react readily with 0-lactones at C-4 to give excellent yields of 3-alkylmercapto- or 3-arylmercapto-propionic acid (equation 54). For example,... 

Amino-1,2,4-thiadiazoles79 and their 3-alkoxy-, 3-alkylmercapto-, and 3-dialkylamino derivatives84 have been claimed to be useful intermediates in the manufacture of dyes,84 pharmaceuticals,84 and materials valuable in pest control.79 Mono-azo dyes derived from diazotized 5-amino-l,2,4-thiadiazoles and coupling components of the benzene series are especially suitable for dyeing polymeric materials such as acetate rayon, polyamides, polyurethanes, polyesters, and... 

Thioxo and alkylmercapto groups are easily replaced by other groups. The sulfur in the 5-position of the 1,2,4-triazine ring is the most reactive and is replaced initially. Water, alcohols, amines, hydrazine and hydroxylamine can replace the thioxo or alkylmercapto group. Scheme 10 summarizes these reactions. Since the preparation of 3-thioxo-l,2,4-triazines is very easy and proceeds in high yield, these replacement reactions at the 3-position are of much preparative value. 

Peptides can also be cyclized through their side-chain functionalities (e.g. using lysine, cysteine, glutamic acid, or aspartic acid [68-71]), or with the aid of synthetic spacers ([72] see also Table 8.5). Examples have been reported of the preparation of cyclic peptides using safety-catch linkers (e.g. (4-alkylmercapto)phenol [62], sulfonamide [73], or hydrazide [74]), 2-nitrophenyl ester attachment [61], or oxime ester... 

Die Mercaptanolyse von 14 in HBr/Eisessig liefert in guten Ausbeuten oc-Ketosaure-mercaptole (oder a-Alkylmercapto-acrylsauren) und 2.2.2-Trifluor-l-alkylmercapto-athylamin-hydrobromide (51) i 5,20i> ... 

Thiazinonium perchlorate 242 also reacts at the 2 position of the heteroring with such 1,3-dinucleophiles as alkylisothioureas and guanidines. After recyclization, alkylmercapto- and aminotriazines 243 were obtained (87MI1) (Scheme 95). 

---