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1.
L. A. Ignatova A. E. Gekhman M. A. Spektor P. L. Ovechkin B. V. Unkovskil 《Chemistry of Heterocyclic Compounds》1974,10(6):662-665
4,4,6-Trimethyl-2-methylarylamino-4H-1,3-oxazines were synthesized by intramolecular cyclization of N-oxoalkyl-S-methylisothioureas.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 764–767, June, 1974. 相似文献
2.
P. L. Ovechkin L. A. Ignatova A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1974,10(3):310-312
N-Aryl-N′-(2-methyl-4-hydroxy-2-pentyl)thioureas are cyclized in acidic media to 4,4,6-trimethyl-2-arylimino-5,6-dihydro-4H-1,3-thiazines, the methylation of which with methyl iodide gives 4,4,6-trimethyl-2-methylarylamino-5,6-dihydro-4H-1,3-thiazines. 3,4,4,6-Tetramethyl-2-aryliminotetrahydro-1,3-thiazines were synthesized by cyclization of Naryl-N′-methyl-N′-(2-methyl-4-hydroxy-2-pentyl)thioureas. 相似文献
3.
E. M. Peresleni L. A. Ignatova P. L. Ovechkin A. P. Engoyan Yu. N. Sheinker B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1975,11(12):1370-1374
It is shown by means of the IR, UV, and PMR spectra of substituted 2-amino-4H-1,3-thiazines that they exist primarily in the amino form in the crystalline state and in solution. 相似文献
4.
2-Methylthio-4H-1,3-thiazines or their mixtures with 5-alkylidene-4H-5,6-dihydro-1,3-thiazines were obtained by cyclization of methyl N-3-oxoalkyldithiocarbamates in sulfuric acid. The regiospecificity of the reaction is determined by the structures of the starting compounds. The structures of the synthesized thiazines were confirmed by spectral methods of analysis (IR and 1H and 13C spectroscopy).Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 991–993, July, 1992. 相似文献
5.
Peresleni E. M. Engoyan A. P. Zotova T. D. Sheinker Yu. N. Ignatova L. A. Unkovskii B. V. 《Chemistry of Heterocyclic Compounds》1977,13(3):278-284
It is shown by means of IR, PMR, and UV spectra that 4,4,6-trimethyl-2-arylamino-5, 6-dihydro-4H-1,3-thlazines and 4,4,6-trimethyl-2-arylamino-5,6-dihydro-4H-1,3-oxazines in the crystalline state and in solution exist primarily in the amino form. It was found that ionization to give cations proceeds more readily in the case of 1,3-oxazines than in the case of 1,3-thiazines. In addition, a decrease in the ability to undergo intermolecular association and a decrease in the energy barrier to rotation about the N-heteroring bond are observed for 1,3-oxazines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 346–352, March, 1977. 相似文献
6.
L. A. Ignatova A. E. Gekhman P. L. Ovechkin B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1974,10(3):307-309
3,4,4,6-Tetramethyl-2-aryliminotetrahydro-1,3-oxazines were synthesized by intramolecular cyclization of N-aryl-N′-methyl-N′-(2-methyl-4-hydroxy-2-pentyl)-S-methylisothioureas. 4,4,6-Trimethyl-2-(N-methyl-N-arylamino)-5,6-dihydro-4H-1,3-oxazines were obtained by methylation of 4,4,6-trimethyl-2-arylamino-5,6-dihydro-4H-1,3-oxazines. 相似文献
7.
Data on the methods of production, chemical properties, and biological activity of unsaturated 4H-1,3-oxazines are generalized.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 291–308, March, 1994. 相似文献
8.
L. A. Ignatova P. L. Ovechkin A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1976,12(12):1333-1336
The relative basicities of 4,4,6-trimethyl-2-arylamino-5,6-dihydro-4H-1,3-thiazines and 4,4,6-trimethyl-2-arylamino-5, 6-dihydro-4H-1,3-oxazines, which are capable of amine-imine tautomerism, and of model compounds with fixed amine and imine structures were determined by potentiometric titration in methanol. Good correlation of the pK
a
values with the Hammett constants in the investigated reaction series was found. The inapplicability of the use of the pK
a
values of model compounds for the determination of the tautomeric equilibrium constants in the case of some N-heterocyclic amines of nonaromatic character with an aryl substituent attached to the exocyclic nitrogen atom of the amidine fragment of the molecule is demonstrated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 12, pp. 1621–1624, December, 1976. 相似文献
9.
P. L. Ovechkin L. A. Ignatova B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1972,8(7):856-858
The synthesis of 3,4,4,6-tetramethyl-2-arylimino-2,3-dihydro-4H-1,3-thiazines, which have a fixed imino structure, was accomplished by two methods: by intramolecular rearrangement of 1,4,6,6-tetramethyl-3-aryl-1,2,3,6-tetrahydropyrimidine-2-thiones and by amination of 3,4,4,6-tetramethyl-2,3-dihydro-4H-1,3-thiazine-2-thione methiodide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 941–943, July, 1972. 相似文献
10.
Facile Yb(OTf)3 promoted one-pot synthesis of polyhydroquinoline derivatives through Hantzsch reaction 总被引:1,自引:0,他引:1
Yb(OTf)3 catalyzed efficient Hantzsch reaction via four-component coupling reactions of aldehydes, dimedone, ethyl acetoacetate and ammonium acetate at ambient temperature was described as the preparation of polyhydroquinoline derivatives. The process presented here is operationally simple, environmentally benign and has excellent yield. Furthermore, the catalyst can be recovered conveniently and reused efficiently. 相似文献
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Several allylic isothiuronium salts 6 have been shown to yield 4-substituted 2-amino-5,6-dihydro-4H-1,3-thiazines ( 2 ; R3 = H) and the 2-phenylimino compound 10 on exposure to trifluoroacetic acid or trifluoroacetic acid-stannic chloride. The overall process constitutes a convenient transformation of readily available ketones or aldehydes 3 into the target hetero-cycles. The scope and limitations of this approach are discussed in terms of carbenium ion intermediates ( 7 ). Whereas this method successfully led to the imidazo[2,l-b][1,3]thiazine 13 (93% from 12 ), its application to the synthesis of 2-amino-2-thiazolines (eg. 14 → 15 ) or imidazo-[2,1-b]thiazoles (eg. 16 → 17 ) was unsuccessful. The 2-acetylimino derivatives 9 were found to be useful for purification of the 2-aminothiazines. 相似文献
13.
P. L. Ovechkin L. A. Ignatova B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1971,7(7):882-885
A comparison of the IR and UV spectra of 2-alkyl(aralkyl)amino-4H-1,3-thiazines with the spectra of model compounds showed that the amino form of the aminothiazines predominates. The basicities of the synthesized compounds were determined, and the structure of the cation formed on protonation is discussed.Translated from Khimiya Geterotsiklicheskikh Soedinenii. No. 7, pp. 946–949, July, 1971. 相似文献
14.
L. A. Ignatova P. L. Ovechkin M. Z. Branzburg A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1972,8(8):939-942
4,4,6-Trimethyl-2-alkyl(aryl)amino-5,6-dihydro-4H-1,3-oxazines were synthesized via two methods: amination of 4,4,6-trimetiiyl-2-methylthio-5,6-dihydro-4H-1,3-oxazine and cyclization of N-aryl-N-(2-methyl-4-hydroxy-2-amyl)-S-methylisothiourea.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1037–1040, August, 1972. 相似文献
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17.
Herrera A Martínez-Alvarez R Ramiro P Sánchez A Torres R 《The Journal of organic chemistry》2004,69(13):4545-4547
Substituted (4Z)-4-benzylidene-2-methyl-4H-1,3-benzothiazines (1). and (4Z)-2-ethyl-4-benzylidene-4H-1,3-benzothiazines (2). were synthesized by direct stereoselective reactions of S-phenyl ethanethioate or S-phenyl propanethioate with substituted benzyl nitriles in the presence of triflic anhydride. 相似文献
18.
P. L. Ovechkin L. A. Ignatova A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1972,8(7):852-855
The reaction of 2-isothiocyano-2-methyl-4-pentanone with substituted anilines gave 4,6,6-trimethyl-3-aryl-1,2,3,6-tetrahydropyrimidine-2-thiones, which are converted to the isomeric 4,4,6-trimethyl-2-arylamino-4H-1,3-thiazines by intramolecular rearrangement by heating with hydrochloric acid. In order to study the structure and amino-imino tautomerism of the aminothiazines, their analogs with a fixed amine structure were obtained. The synthesis of model compounds was accomplished by reaction of 2-isothiocyano-2-methyl-4-pentanone with m- and p-substituted N-methylanilines and subsequent cyclization of the resulting N-methyl-N-aryl-N-(2-methyl-4-oxo-2-amyl)thioureas to 4,4,6-trimethyl-2-methylarylamino-4H-1,3-thiazines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 937–940, July, 197 相似文献
19.
Reaction of 2-formylbenzoates with hexamethyldisilazane and diethyl phosphite in the presence of Yb(OTf)3 proceeded smoothly at room temperature to afford addition adducts, which were readily cyclized to 3-phosphonate phthalides by adding trifluoroacetic acid (TFA). The reactions employing Sc(OTf)3 instead of Yb(OTf)3 produced 3-phosphonate isoindolinones without addition of TFA. 相似文献
20.
L. A. Ignatova P. L. Ovechkin A. E. Gekhman B. V. Unkovskii 《Chemistry of Heterocyclic Compounds》1975,11(6):675-678
The relative basicities of 4,4,6-trimethyl-2-arylamino-4H-1,3-thiazines, which are capable of amine-imine tautomerism, and of model compounds with fixed amino and imino structures were determined by potentiometric titration in methanol. Good correlation was observed between the pKa values and the Hammett σ constants in the investigated reaction series. The anomalous pKa values of the model amines and imines are explained by the different character of the electronic interactions in them, which is due to the change in the three-dimensional orientation of the aromatic ring and the amidine fragment. 相似文献