Thiosemicarbazide, reaction with

Thiophene-carbo lic acids, 239, 240 Thiopyrimidines, dialkyl-, 24 Thiosemicarbazides, reaction with nitrous acid, 263... 

Thiosemicarbazides (141), Rj = H, yield the 2-hydrazinothiazoles (Scheme 68). Compound 142, R] = H, on reaction with o-halocarbonyl... 

Hydrazinotriazine 749 was prepared by the condensation of the respective quinone with thiosemicarbazide followed by sequential cyclization, chlorination with phosphorus oxychloride, and reaction with hydrazine (88JHC1139). Cyclocondensation of 749 with formic acid or carbon disulfide gave triazolotriazines 750 (88JHC1139) (Scheme 156). 

Thionyl fluoride, as by-product in sulfur tetrafluoride reactions, 41, 105 toxidty of, 41,105 Thiophene-2-OL, 43, 55 2(5H)-Thiophenone, 43, 55 Thiosemicarbazide, in synthesis of 1,2,4 triazole, 40, 99 reaction with formic acid to yield l-formyl-3-thiosemicarbazide, 40,99... 

Dihydropyrrole a-ketoester 423 when reacted with 2,2,2-trichloroethyl carbazate in refluxing xylene underwent smooth cycloaddition to afford cycloadduct 48 in 86% yield. Reaction of 423 with thiosemicarbazide in acetic acid yielded a product mixture to give the tetracycle 48. Its benzyloxycarbonyl group was cleaved by reaction with HBr to give crystalline 424 <2002JOG7880> (Scheme 94). 

A new synthetic route for functionalized polyhydroxyalkyl-pyrimidines starting from unprotected aldoses and based on montmorillonite K-10 catalysis and solvent-free microwave irradiation conditions, has been reported by Yadav et al,m Thus, reaction of D-glucose and D-xylose with semicarbazide or thiosemicarbazide (186) in the presence of montmorillonite K-10, under microwave irradiation, proceeded via domino cycloisomerization, dehydrazination, and dehydration of the intermediate semi- or thiosemicarbazones (187) to afford l,3-oxazin-2-ones or l,3-oxazine-2-thiones (188) in one single step and in yields between 79% and 85% (Scheme 34). Other mineral catalysts tested, such as silica gel and basic alumina, were far less effective for this transformation and only silica gel was active at all, giving low yields (15-28%) of compounds 188a-d. The l,3-oxazin-2-ones(thiones) thus synthesized were subsequently converted into the target pyrimidines by reaction with aromatic... 

Alternatively, the starting material has the isoquinoline ring, as in phtha-lonimides 179, which on reaction with thiosemicarbazide or aminoguani-dine gave the intermediates 180, which were subsequently cyclized (75ZOR2407) with base to give 181. 

Thus, (dimorpholinophosphoryl)formonitrile oxide undergoes 1,3-addition reactions with HC1, HI, primary and secondary amines, acylhydrazines, and even with thiourea or thiosemicarbazide (Scheme 1.13) (98). The former gives (dimor-pholinophosphoryl)isothiocyanate and urea. Those products might arise from a retro destruction of the unstable 1,3,5-oxathiazoline. The latter transforms to the isothiocyanate, the product of addition of a second molecule of thiosemicarbazide. (98). 

Ph) is transformed by reaction with aniline into the l,2,4-triazole-3-thione (161, R = Me, = Ph) the presumption that this transformation involves the thiosemicarbazide 160b as an intermediate is supported by the isolation of the derivative 160c by a similar reaction with diethylaraine. ... 

The basic amino group of the 1-position in semicarbazide or thiosemi-carbazide may be used to react by a substitution reaction with activated halides [52], ethers [51], hydroxy [53], phenoxy [54], and amino groups [55] to yield substituted 1-semicarbazides or thiosemicarbazides. In addition, the amino group of the 1-position may add to electron-deficient double bonds [56]. Formaldehyde and other aldehydes may add to all the available free NH groups to give methylol, alkylol, or polymeric products under basic conditions [57]. Aldehydes or ketenes usually give semicarbazone derivatives, and these in turn are used analytically to identify the purity or structure of a known aldehyde [3]. 

Amino-5-alkyl- or 5-phenyI-l,3,4-thiadiazoles are prepared most conveniently from thiosemicarbazide. For example, benzalthiosemicarbazone by oxidation with iron(III) chloride gives the 5-phenyl derivative. Thiosemicarbazide is also used in the synthesis of 2-amino-5-mercapto-l,3,4-thiadiazole by reaction with carbon disulfide. The product may be alkylated to yield the 5-alkylthio derivatives using a variety of alkylating agents (58MI11201). 

Some new 5-(benzylamino)thiatriazoles have been prepared by standard methods.12 5-(Tetra-0-acetyl-/T-D-glucopyranosylamino)-thia-triazole was prepared by the action of HN02 on 4-(tetra-0-acetyl-/3-D-glucopyranosyl)thiosemicarbazide as well as from hydrogen azide and tetra-0-acetyl-/J-D glucopyranosyl isothiocyanate.62 Substituted 5-aminothiatriazoles may be obtained from C-sulfonylthioformamides on reaction with azide ion.63... 

Carbonylation occurs by the oxidation of some amino acid side chains into ketone or aldehyde derivatives by reactions with compounds of lipid oxidation or by glycoxidation with reducing sugars. These protein-carbonyl compounds are markers of protein oxidation, and recently, several carbonylated proteins and protein oxidation sites in milk (96), meat (97), and fishes (98) have been identified using a classical bottom-up proteomics approach based on 2-DE and MS/MS. Specific labeling of protein carbonyls using fluorescein-5-thiosemicarbazide has been developed and combined with 2-DE and... 

Treatment of thiosemicarbazide hydrochloride with acetic monochloro-acetic anhydride affords 121.168 Further reaction with the anhydride gives 122, which readily cyclizes to the 6,5-fused ring system 123 [Eq. (38)].155... 

For cyclization of thiosemicarbazides a large variety of reagents is available, and several of them have been used from the beginning of the century. This applies, for example, to the reaction with aldehydes to form thiosemicarbazones, which are then cyclized by oxida-... 

Method (a) has been used by Jensen and Pedersen, who prepared 2-phenyl-l,3,4-thiadiazoline-5(4)-thione (110) in 94% yield from thiobenzhydrazide (11) and carbon disulfide in ethanolic potassium hydroxide at room temperature. The 2-benzyl analog was obtained in the same way from phenylthioacethydrazide. This method will probably gain importance through the increased availability of thiohydrazides due to the work of Jensen et Thiosemicarbazide has been used for the preparation of 2-amino-l,3,4-thiadiazoline-5(4)-thione (111) in 92% yield through reaction with carbon disulfide in ethanol in an autoclave at 140° without a base, and in 82 % yield through reaction with carbon disulfide and sodium carbonate in refluxing ethanol. ... 

The formation of alternative heterocycles can be the main reaction with semicarbazides or thiosemicarbazides which are used extensively in the preparations of triazolinones and triazolinethiones. Aminoguanidines can give rise to isomeric triazoles. The preferred formation of thiadiazole (157) from the 1-acylthiosemicarbazide (Scheme 66) is explained by the protonation of N-4 in strong acid with accompanying loss of nucleophilicity, while in the presence of base its nucleophilic character is enhanced 73JOC3947) and (158) is obtained. 

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