Synthesis of 2-Aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones and 7-Aryl-2,3,6,7-tetrahydro-5H-imidazo[2,1-b]-1,3-thiazin-5-ones

The reaction of 2-mercaptobenzimidazole, 5-ethoxy-2-mercaptobenzimidazole, and 2-mercaptoimidazoline with cinnamoyl chloride, its derivatives, and heteroanalogs was studied. Convenient methods were found for the synthesis of 2-aryl-2,3-dihydro-4H-[1,3]thiazino[3,2-a]benzimidazol-4-ones and 7-aryl-2,3,6,7-tetrahydro-5H-imidazo[2,1-b]-1,3-thiazin-5-ones.     

2,2-di(fluoroalkyl)-5,5-difluoro-1,3-dioxolan-4-ones

The condensation of fluoroacetones with oxalyl fluoride in the presence of potassium fluoride has been shown to yield 2,2-di(fluoroalkyl)-5,5-difluoro-1,3-dioxolan-4-ones.     

4H-3,1-Benzoxazin-4-ones methoxy-substituted 2-(2-arenesulfonylaminophenyl)-4H-3,1-benzoxazin-4-ones

Methoxy-substituted 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-one and 2-phenyl-4H-3,1-benzoxazin-4-one were synthesized. Their UV, IR, and luminescence spectra were studied. The position of the methoxy group affects the strength of the intramolecular hydrogen bond (IHB). The luminescence properties of methoxy-substituted 2-(2-tosylaminophenyl)-4H-3,1-benzoxazin-4-ones are associated with the strength of the IHB. The luminescence maximum is shifted to the short-wave region with strengthening of the IHB, and the luminescence intensity increase simultaneously.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1028–1032, August, 1971.The authors thank Yu. S. Ryabokobylko and A. O. Zisman for measuring the absorption spectra in the IR and UV regions.     

Synthesis,steric structure,and biological activity of 5-methyl-2-(morpholin-4-ylamino)-5,6-dihydro-4H-1,3-thiazin-4-one

Russian Journal of General Chemistry - New 5,6-dihydro-1,3-thiazin-4-one derivatives have been synthesized by one-pot reaction of morpholin-4-amine and adamantan-1-amine with methacryloyl...     

Synthesis and Crystal Structure of 4-tert-Butyl-6-（4-chlorophenyl）-3,6- dihydro-2H-1,3-thiazin-2-iminium Chloride

The title compound, 4-tert-butyl-6-（4-chlorophenyl）-3,6-dihydro-2H-1,3-thiazin- 2-iminium chloride （C14H18C12N2S）, has been synthesized by the reaction of 1-（4-chlorophenyl）- 4,4-dimethylpent-1-en-3-one with thiourea, and its crystal structure was determined by single- crystal X-ray diffraction. The crystal belongs to the monoclinic system, space group P211c with a = 16.3064（11）, b = 9.4471（6）, c = 11.2626 （8）A, β = 108.400（1）°, Z = 4, V = 1646.28（19） A^3, Mr = 317.26, Dc = 1.280 g/cm^3, S = 1.078,μ = 0.510 mm^-1, F（000） = 664, the final R = 0.0514 and wR = 0.1412 for 3210 observed reflections （I 〉 2σ（I））. The thiazine ring system displays a twisted boat conformation, and three N-H,..Cl hydrogen bonds exist in the crystal. The combination of two N-H...Cl hydrogen bonds generate an R2^1 （6） ring.     

Synthesis of 2,3,5,6-tetrahydro-4H-1,4-thiazin-3-one 1,1-dioxides from methyl (styrylsulfonyl)acetate

Methyl (styrylsulfonyl)acetate ( 1 ) was shown to be a useful building block for the synthesis of 5-phenyl-2,3,5,6–4H-tetrahydro-1,4-thiazin-3-one (2), its 4-amino 3 , and 4-hydroxy 4 derivatives. Their 2-spirocyclopropanes 9, 10 , and 11 , and 2,7-diphenyl-6,7-dihydro-8H-pyrimido[5,4-b][1,4]thiazinc 5,5-dioxide ( 18 ) were also prepared from 1 .     

New method for the synthesis of the 1,3-thiazine system. 2-phenylamino-5,6-dihydro-4H-1,3-thiazin-5-ones

Treatment of N-phenylthioureidoalkyl--diazo ketones with acids leads to 2-phenyl-amino-5,6-dihydro-4H-1,3-thiazin-5-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1327–1330, October, 1980.     

Facile synthesis of 2-(substituted amino)-4H-thieno[3,2-e]-1,3-thiazin-4-ones

Interaction between 2,5-dichlorothiophene-3-carbonyl isothiocyanate, accessible via 2,5-dichlorothiophene-3-carbonyl chloride, and model heterocyclic amines produced the respective 2,5-dichloro-N-(substituted aminocarbonothioyl)thiophene-3-carboxamides. Upon heating, the deprotonated form of the latter underwent intramolecular cyclization to deliver the corresponding 2-(substituted amino)-4H-thieno[3,2-e]-1,3-thiazin-4-ones. The structures of these new bicyclic derivatives and their acyclic precursors are based on microanalytical and spectral (IR, MS, and NMR) data.     

Synthesis of 2H-1,4-thiazin-3(4H)-one 1-oxide and 2H-1,4-thiazin-3-(4H)-one 1,1-dioxide,structural analogs of uracil

The synthesis of 1,4-thiazine 1-oxide and 1,1-dioxide analogs of the antibiotic emimycin is described. Reaction of methylthioglycolate with 1-bromo-2,2-diethoxyethane gave methyl (2,2-diethoxyethylthio)acetate ( 2 ). Treatment of 2 with methanolic ammonia followed by cyclization furnished 2H-1,4-thiazin-3(4H)-one ( 5 ). Oxidation of 5 with m-chloroperoxybenzoic acid converted it to 2H-1,4-thiazin-3(4H)-one 1-oxide ( 6 ). Oxidation of 2 with potassium permanganate, followed by treatment with methanolic ammonia, and cyclization gave 2H-1,4-thiazin-3(4H)-one 1,1-dioxide.     

Synthesis of 5-[bromo(aryl)methyl]-2,2-dimethyl-1,3-oxazolidin-4-ones

A Darzens condensation of α-chloroacetamide with aromatic aldehydes furnished a series of 3-aryl-2,3-epoxypropionamides, which were further converted to 5-[bromo(aryl)methyl]-2,2-dimethyl-1,3-oxazolidin-2-ones.     

Synthesis of allylic thiocyanates and novel 1,3-thiazin-4-ones from 2-(bromomethyl)alkenoates and S-nucleophiles in aqueous medium

Allylic thiocyanates and novel heterocycles containing the 1,3-thiazin-4-one core are easily obtained in high yields and mild conditions by nucleophilic displacement of 2-(bromomethyl)alkenoates (derived from Morita-Baylis-Hillman adducts) with sulphur-centred nucleophiles in aqueous acetone at 25 °C. Treatment of allylic bromides with NaSCN gave the corresponding (Z)-2-(thiocyanomethyl)alkenoates, while the reaction with thiourea followed by a basic work-up selectively produced (5Z)-2-amino-5-arylidene-1,3-thiazin-4-ones. The structural assignments were confirmed by X-ray diffraction analysis.     

Azines and azoles: CXXIX. Synthesis,structure, and some reactions of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-ones

Reactions of 2-aryl-4-chloro-6H-1,3-thiazin-6-ones with sodium sulfide in aqueous alcohol at 18–20°C led to the formation of a readily separable mixture of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-one sodium salts (yield >70%) and bis(2-aryl-6-oxo-6H-1,3-thiazin-4-yl) sulfides (<10%). The latter can also be obtained in more than 50% yield by treatment of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-one sodium salts with 2-aryl-4-chloro-6H-1,3-thiazin-6-ones. Methylation of 2-aryl-4-sulfanyl-6H-1,3-thiazin-6-ones afforded the corresponding methylsulfanyl derivatives (yield >90%) regardless of the alkylating agent, solvent, temperature, reactant concentration, and their ratio. 2-Aryl-4-sulfanyl-6H-1,3-thiazin-6-ones in the crystalline state and in solutions in polar and nonpolar protic and aprotic solvents exist preferentially as 4-sulfanyl-6-oxo tautomers, and they undergo almost complete ionization in neutral aqueous, alcoholic, and aqueous-alcoholic media (pK _a = 4.3). Reactions of 4-sulfanyl-2-phenyl-6H-1,3-thiazin-6-one with ammonia, amines, and difunctional N-centered nucleophiles involve cleavage of the C⁶-S bond in the thiazine ring and subsequent recyclization of linear intermediates to pyrimidines and diazole derivatives. The structure of the isolated compounds was confiirmed by ¹H and ¹³C NMR, IR, and UV spectra.     

2,2-Bis(methoxy- and ethoxy-NNO-azoxy)propane-1,3-diol sulfonates

2,2-Bis(alkoxy-NNO-azoxy)propane-1,3-diols react with sulfonyl chlorides and trifluoromethanesulfonic anhydride in the presence of bases affording previously unknown methane-, trifluoromethane-, benzene and toluenesulfonates (sulfonic esters) of 2-bis(methoxy- and ethoxy-NNO-azoxy)propane-1,3-diols. The triflates are thermally less stable than mesylates, benzenesulfonates, and tosylates of the corresponding diols.