2-(Fur-2-yl)naphtho[2,1-d]oxazole. Synthesis and some transformations

The condensation of 1-hydroxy-2-aminonapnthalene with furoyl chloride in 1-methyl-2-pyrrolidone medium afforded 2-(fur-2-yl)naphtho[2,1-d]oxazole. It was involved in reactions of electrophylic substitution like nitration, bromination, sulfonation, formylation, and acylation. In all cases the substituent enters in position 2 of the furan ring.     

Synthesis and properties of 2-amino-5-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazoles

The reaction of thiourea of N-substituted thioureas with 2-(2-N,N-diethylaminoethenyl)-3,5,6-trichloro-1,4-benzoquinone leads, through the formation of 2,5-dihydroxy-3,4,6,7-tetrachlorocoumaran, to 2-amino-5-(2,5-dihydroxy-3,4,6-trichlorophenyl)thiazoles (which exist in the form of betaines), the oxidation of which leads to 2-amino-5-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazoles.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 692–698, May, 1988.     

Synthesis of 3-substituted 5-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazoline-2-thiones

By the interaction of 2, 5-dihydroxy-3, 4, 6, 7-tetrachloro-2, 3-dihydrobenzo(bjfuran with salts of N-monosubstituted dithiocarbamic acids, followed by oxidation of the resulting products by benzoquinone, 3-substituted S-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazoline-2-thiones have been obtained. An alternative method of synthesis is also proposed, including reaction of the original benzofuran with N-substituted N',N'-dimethylthioureas, cyclization of the resulting thiouronium salt to form 3-substituted 5-(2, S-dihydroxy-3, 4, 6-trichlorophenyl)-2-dimethylattiinothiazolium cations, treatment of these cations with hydrogen sulfide, and subsequent oxidation of the hydroquinone fragment to quinone.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 111–114, January, 1994.     

Preparation of 3-substituted 2-dimethylamino-5-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazolium salts

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 427–428, March, 1992.     

Synthesis and properties of 2-(2-thienyl)naphtho[2,1-d]oxazole

The condensation of 2-aminonaphthalen-1-ol with thiophene-2-carbonyl chloride in 1-methylpyrrolidin-2-one gave 2-(2-thienyl)naphtho[2,1-d]oxazole which was brought into electrophilic substitution reactions: nitration, bromination, sulfonation, formylation, and acylation. Depending on the conditions, the attack by electrophile was directed at both thiophene ring and naphthalene fragment in the thienylnaphthooxazole molecule.     

Synthesis of 3-N,N-Dialkylamino-5-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazoline-2-thiones

N,N-Dialkylhydrazides of S-(4,6,7-trichloro-2,5-dihydroxy-2,3-dihydrobenzo[b]-3-furanyl)dithiocarbonic acids have been obtained by the reaction of 3,4,6,7-tetrachloro-2,5-dihydroxy-2,3-dihydrobenzo[b]furan with N,N-dialkylhydrazinium salts of N,N-dialkylhydrazides of dithiocarbonic acids. Recyclization in boiling ethanol in the presence of conc. HCl with subsequent oxidation leads to the formation of 3-N,N-dialkylamino-5-(3,5,6-trichloro-1,4-benzoquinon-2-yl)thiazoline-2-thiones. An attempt at recyclization in boiling trifluoroacetic acid led to the formation of 3-N,N-dialkylamino-5,6,8-trichloro-7-hydroxy-2,3,3a,8b-tetrahydrothiazolo[4,5-b]benzo[d]furane-2-thiones.     

Synthesis and Some Reactions of 2-(Thien-2-yl)naphtho[1,2-d]thiazole

Russian Journal of General Chemistry - Condensation of 1-aminonaphthalene with thiophene-2-carbonyl chloride in 2-propanol furnished N-(1-naphthyl)thiophene-2-carboxamide, the treatment of which...     

Synthesis of 6-aminobenzo[b]naphtho[2,1-d]thiophene

6-Aminobenzo[b]naphtho[2,1-d]thiophene has been prepared by two different routes, one, a one-pot synthesis.     

Cyanine dyes from naphtho [1,2-6]thiazolo[3,2-d][1,4]thiazine

Deeply colored cyanine dyes have been synthesized from the previously unknown 3-methyl-12H-naphtho[1,2-b]thiazolo[3,2-d][1,4]thiazinium salts. It is assumed that the deep color of the new cyanines is connected with the conversion of the nonaromatic 1,4-thiazine ring in the dye molecule into an aromatic thiazine ring with three double bonds in a six-membered ring.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 9, pp. 1282–1284, September, 1973.     

Benzo[b]naphtho[2,1-d]thiophene (thiachrysene) derivatives as potential carcinostatic molecules

About twenty compounds of the benzo[b]naphtho[2,1-d]thiophene series have been synthesized, namely, 6-amino derivatives, with the aim of biological testing as possible carcinostatic molecules.     

Synthesis and some transformations of 2-(2-thienyl)naphtho[1,2-d]oxazole

Condensation of 1-amino-2-hydroxynaphthalene with thenoyl chloride in 1-methyl-2-pyrrolidinone medium afforded 2-(2-thienyl)naphtho[1,2-d]oxazole. The latter was brought into electrophilic substitution reactions like nitration, bromination, sulfonation, formylation, and acylation. The reactions proceeded via electrophilic attack at the 5-position of the thiophene ring, but the nitration and bromination occurred involving both the thiophene and naphthalene fragments.     

Synthesis and molecular structure of 3-[5-(quinolin-2-yl)penta-1,4-dien-1-yl]-1,4-benzodioxin-2-one

Acid-catalyzed reaction of 6,10a-dihydroxy-3,4a,7,9-tetra(tert-butyl)-1,2,4a,10a-tetrahydrodibenzo-[b,e][1,4]dioxine-1,2-dione with 4-chloro-2,7,8-trimethylquinoline gave previously unknown 3,6,8-tri-tert-butyl-3-[2-tert-butyl-5-(4-chloro-7,8-dimethylquinolin-2-yl)-4-hydroxy-3-oxopenta-1,4-dien-1-yl]-5-hydroxy-1,4-benzodioxin-2-one whose structure was determined by X-ray analysis. The energy and structure parameters of possible isomers of the product in the gas phase and in solution were estimated by PBE0/6-31G** quantum-chemical calculations.     

Unexpected formation of 6-methyl-4-(5-methylfuran-2-yl)-2-ethylsulfanylpyridine-3-carbonitrile from 2-methyl-4-(5-methylfuran-2-yl)-N-o-tolyl-5-cyano-6-ethylsulfanyl-1,4-dihydropyridine-3-carboxamide

Russian Journal of Organic Chemistry -     

ESIPT inspired fluorescent 2-(4-benzo[d]oxazol-2-yl)naphtho[1,2-d]oxazol-2-yl)phenol: experimental and DFT based approach to photophysical properties

ESIPT inspired fluorescent 2-(4-benzo[d]oxazol-2-yl)naphtho[1,2-d]oxazol-2-yl)phenol was synthesized from 1-amino-3-(1,3-benzoxazol-2-yl)naphthalen-2-ol. Photophysical behavior of the synthesized compound was studied using UV–visible and fluorescence spectroscopy in polar and non-polar solvents. The synthesized naphthoxazolyl benzoxazole is fluorescent and very sensitive to the micro-environment. It shows a single absorption and dual emission in non-polar solvents with large Stokes shift originating from Excited State Intramolecular Proton Transfer while in polar solvents only a single short wavelength emission is observed. Experimental absorption and emission wavelengths are in good agreement with those predicted using the Time-Dependent Density Functional Theory (TD-DFT) [B3LYP/6-31G(d)]. The largest wavelength difference between the experimental and computed absorption maxima was 16 nm (acetonitrile) and 7 nm (ethyl acetate, THF, and 1,4-dioxane) in the short and long wavelength regions, respectively. A largest difference of 25 nm was observed for the short wavelength emission in DMF and 22 nm for the longer wavelength emission in chloroform.