1,3,-Thiazines disulfide

In the reaction of 2-isopropylidene-l-cyclopentanone 201 with carbon disulfide and ammonia, the perhydrocyclopenta[e][l,3]thiazine-2-thione derivative 204 was formed. The probable intermediates of the reaction are the Michael adduct 202 and the 2-imino-l-cyclopentanedithiocarbamic acid derivative 203. Under similar conditions, the related alkylidene derivatives gave the corresponding 3-substituted-2-imino-l-cyclopentanedithio-carbamic acid derivatives. Further substituted derivatives and homologs of 204 were also synthesized (74AKZ319), but the stereochemistry of these compounds was not investigated [73JCS(P1)1009]. 

The reaction of cyclobutanone oxime 277 with S2GI2 affords the conjugated 1,2-thiazine 70 in 45% yield (Equation 38) <1996JOC9178>. The proposed mechanism for this transformation involves the intermediate nitrile 278, which reacts to form imino-disulfide 279. Following ring contraction of 279 and further chlorination, product 70, whose structure was confirmed by X-ray analysis, is obtained. 

The spiro compound 15 is obtained in excellent yield by the cycloaddition of 3-(4-fluorophenylimino)indolin-2-one with mercaptopropionic acid under microwave irradiation <2003SUL201>. Treatment under basic conditions of 2,3-dihalopropylamines with carbon disulfide results in the formation of two isomeric products 5-halotetrahydro-l,3-thiazine-2-thione 204 and 5-(halomethyl)thiazolidine-2-thione 205 <2002CHE1533>. 

Aminoquinoxaline-3-thione (166) reacts with cr-chloroesters under alkaline conditions, and (2-aminoquinoxaline)thioglycollic acids (167) are obtained. With et-haloketones in the presence of alkali, ring closure takes place and quinoxalino]2,3-6] [ l,4]thiazines, such as 168 are isolated.174 Photolysis of 3-methylquinoxaline-2-thione in ethanol or chloroform yields 3-methyl-2-quinoxalyl disulfide.175... 

Syntheses based not only on compounds 426 but also on other 1,8-disubstituted naphthalenes have been described. Thus, decomposition of peri-diazonium-substituted azides 432 in carbon disulfide, proceeding by the free radical mechanism, yields naphtho[de]-l,3-thiazine-2-thiones 433... 

C-Enamino-imines obtained by photolysis of l//-pyrimidin-2-ones have been treated with carbon disulfide, giving 2//-l,3-thiazine-2-thiones (22) and/or l-aryl-l//-pyrimidine-2-thiones (23) (Scheme 13) [82JCS(P1)2149]. 

Group 3 volatiles, formed by further interactions, can reach even lower threshold values than those mentioned so far, particularly when sulfur is involved, usually derived by the break down of cysteine (bis(2-methyl-3-furyl) disulfide, 0.00002 2-methyl-3-furanthiol, 0.0004 2-furylmethanethiol, 0.005 dimethyl trisulfide, 0.01 dimethyl disulfide, 0.16 dimethyl sulfide, 0.3 hydrogen sulfide, 10). Into some volatile sulfur compounds other atoms as well as the sulfur of cysteine are incorporated (2-acetylthiazoline, 1 5-acetyl-2,3-dihydro-l,4-thiazine, 1.25 2-acetylthiazole, 10). Other volatiles are more likely to be derived from methionine (methanethiol, 0.2). 

Finally, 96 (and its 2-methyl analog), when heated in pyridine with carbon disulfide and triethylamine (bath at 115°C, 6 h), yielded 95% of 7- and 8-methyl-1,6-dihydro-8-azapurine-2-thione. Derivatives of a new ring system were produced instead of azapurines when the 3-methyl and 3-benzyl analogs of 96 were treated similarly, giving 3-alkyl-3,7-dihydro-3//-1,2,3-triazolo[4,5-[Pg.169]

A derivative of a hitherto unknown nucleus was produced when 4-amino-5-aminomethyl-3-methyltriazole was refluxed with carbon disulfide and triethylamine in pyridine, which yielded 3-methyl-3,7-dihydro-l,2,3-triazolo-[4,5-d][l,3]thiazine-5-thione (98) (3 hr, 53%) the 3-benzyl analog was made similarly (63%) [80JCS(P1)2009]. Cyclization of 4-anilino-5-ethoxycarbonyltriazole with polyphosphoric acid produced 1 f/-triazolo-[4,5-h]quinol-4-one (99) [80EUP(A)2562]. Similarly, ring closure of 4-(2-pyridylamino)triazole-5-carboxylic acid (or its esters) gave l//-pyrido-[l,2-a]-l,2,3-triazolo[4,5-d]pyrimidin-4-one (100) (77GEP2757929). 4-Amino-5-formyl-3-methyltriazole and pentane-2,4-dione, set aside in 20% sulfuric acid, yielded 3,5-dimethyl-3//-l,2,3-triazolo [4,5-6] pyridin-6-yl... 

A procedure was developed (1988JPR585, 1991JPR229, 1993JCR(S)302, 1993MI1) for the synthesis of thienopyrimidinedithiones 28 involving thermal recyclization of thiazines 29, which, in turn, are prepared by the reactions of substituted 2-amino-3-cyanothiophenes 30 with carbon disulfide in the presence of bases. 

In Table 20 are shown the perhydro-l,3-thiazine-2-thiones (CXXII) which, in analogy with the 2-halo amines, are obtained by refluxing carbon disulfide with 3-halo aliphatic amines in alkali (129, lo4, 202, 242, 295). 

The reaction of a-amino ketones with carbon disulfide yields the isomers of 3,4-dihydro-2H-l,3-thiazine-2-thiones as already mentioned in Section II.3. 

Dihydro-l,3-thiazine-6-thiones (262) are obtained from 2-aza-1,3-dienes (263) through cycloaddition reactions with carbon disulfide in the presence of a catalytic amount of boron trifluoride. It is probable that the initial adducts are 2,5-dihydro-1,3-thiazine-6-thiones (264), which are unstable and tautomerize to the observed products (Scheme 50) <86CC1179>. 

Burrows et al., (1972), and some disulfide cation radicals in water solution (68) by Mockel et al., (1974). Cation radicals of pheno-thiazines have also been made in this way in hydrocarbon solutions (Burrows et al., 1973). The technique is very useful in conjunction... 

Both ( )- and (Z)-allyl dithiocarbamates have been stereoselectively prepared in high yields from acetates of MBH adduets in catalyst-free one-pot three-component coupling reactions of carbon disulfide and amine in water under a mild and green procedure (Scheme 3.152). The reaction pathway involves the nucleophilic displacement (-S n2 ) of MBH acetates by dithio-carbamate anions. The utility of these allyl dithiocarbamates has been demonstrated in the synthesis of 3,5-dibenzyl-l,3-thiazines derivatives 344 and 345 (Scheme 3.153). ... 

In a weakly alkaline solution, isothiocyanate reacts with the a-amino group of cysteine (Figure 2.64). The reaction of isothiocyanates with cystine leads to the cleavage of disulfide bond (-S-S-) with the formation of cysteine sulfenic acid and a dithiocarbamic acid ester. Dehydration of this ester yields 5-amino-l,3-thiazine-4-one-3-thione derivative and elimination of hydrogen sulfide produces a cyclic 2-thiazoline-4-carboxylic acid derivative (Figure 2.65). Reaction of cystine with thiocyanates (R-S-C=N), formed by spontaneous isomerisation of isothiocyanates, produces disulfide Cys-S-S-R and -thiocyanoalanine, which cyclises to 2-thiazoline derivative (Figure 2.66). 

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