3.4- Dihydro-3- thieno

Thienyl sulfides with the 2-position of the thiophene ring blocked, e.g., allyl 2-methyl-3-thienyl sulfide (51), also undergo sigmatropic rearrangement when heated in quinoline [Eq. (23)]. 2,6-Dimethyl-2,3-dihydro-thieno[3,4-Z ]thiophene (52) is formed, together with other products. 

Fiessdmann and Pfeiffer" passed HCl at 0° through acetoacetic ester and thioglycolic ester in dcohol to obtain triethyl y3, -bis(carbo-methoxymethylthio)butyrate (169) Dieckmann condensation reportedly furnish ethyl 3,4-dihydroxy-6a-methyl-3a,6a-dihydro-thieno(2,3-b]-thiophene-2-carbOxylate (170) [Eq. (48)]. 

A comparison has been made of the spectra of thienothiophenes 1 and 2 with those of naphthalene and benzo[ft]thiophene and of the spectra of l/f,3i/-thieno[3,4-c]thiophene (112) and of 4,6-dihydro-thieno[3,4-6]thiophene (131) with those of thieno[6]- and thienolc]-cycloalkenes. ... 

Thieno[3,2-c]pyridin-4-one (277) has been prepared by thermal cyclization of 2-thienyl-vinyl isocyanate (Scheme 73) (70BSB301). The derived chloro compound (278) can either be reduced by zinc-acetic acid to (260) or be readily converted into other derivatives by nucleophilic substitution of the halogen. The formation of 4-thiomethyl-6,7-dihydro-thieno[3,2-c]pyridine (280) by cyclization of the isothiocyanate (279) has also been reported (equation 23) (73GEP2318399). 

Russian workers (82KGS118) reported the synthesis of 5,6-dihydro-thieno[2,3-d]pyrimidine 122 by brominating 5-allylpyrimidine-4(3//)-thione 121. 

Reported Yields of 6,7-Dihydro-thieno[3,2-c]pyridines Obtained... 

Upon treatment with CS2 at 170°C, 4,6-dihydro thieno[3,4-d]-l,2,3-thiadiazole (70) yielded 4,6-dihydrothieno[3,4-(/]-1,3-dithiole-2-thione (71), which was a useful intermediate for the synthesis of a novel organic conductor <89TL7249>. 

From 3,4-dibromotetrahydrothiophene 1,1-dioxide in the presence of pyridine and mesitonitrile oxide is obtained 4,4-dioxo-3-(2,4,6-trimethylphenyl)-3a,6a-dihydro-thieno[2,3-d]isoxazoline (172). A second equivalent of nitrile oxide leads to the formation of the 2 1 adduct (173). NMR analysis and crystallographic studies show the formation of the adduct where the regioselectivity corresponds to the oxygen atom of the dipoles bonded to the carbon atom /3 to the sulfone group, the endo nature of the addition, and the anti situation of the two rings in the diadduct (173) (81JOC3502). 

An aqueous dispersion consisting of polyethylene glycol containing a (2,3-dihydro-thieno[3,4-b][l,4]dioxin-2-yl)-methanol terminus has been prepared. This material exhibited electrical conductivities, visible light transmittances, and good processability. 

A reaction vessel was charged with 2-hydroxymethyl-2, 3-dihydro-thieno[3,4-b] [ 1,4] dioxine-5,7-dicarboxylic acid (0.184 mol) dissolved in 500 ml DMAc and then treated with copper dichromate (8.6 g) and 15 drops of quinoline. This mixture was stirred for 2 hours at 150°C and cooled to the ambient temperature. It was poured into EtOAc, and the catalyst was removed by filtration. The filtrate was washed with acidic water and brine, then concentrated, and the product was isolated by distillation at 115°C to 120°C at 0.05 mmHg. 

Preparation of Polyethylene Oxide Substituted (2,3-Dihydro-Thieno[3,4-b] [1,4] Dioxin-2-yl)-Methanol... 

Groenendaal [3] prepared water soluble 4-(2,3-dihydro thieno[3,4-b)][l,4] dioxin-2-yl-methoxy)-butane-l-sulfonic acid sodium salt, (IV), and copolymers with poly(styrenesulphonic acid) having a of 290,000 daltons that were used in electroconductive devices. 

The action of NaBH4 on 141 (X = X = Cl) gave 2-chloro-3,4-dihydro-thieno[3,4-d]pyrimidines 142, which were used for the synthesis of 2-substituted dihydrothieno[3,4-d]pyrimidines via nucleophilic substitution reactions (81JMC376). 

Storr and co-workers at ICI reported the first example of an oxazole-o-quinodimethane in 1990 (Scheme 1.207). FVP of 5-[[(p-chlorobenzoyl)oxy]-methyl]-4-methyloxazole 750 generated oxazole-o-quinodimethane 751. Trapping 751 with thiophenol gave rise to a mixture of 4-methyl-5-[(phenylthio)methyl]ox-azole 752 and 5-methyl-4-[(phenylthio)methyl]oxazole 753, whereas reaction of 751 with sulfur dioxide produced 4,6-dihydro-thieno[3,4-d]oxazole 5,5-dioxide... 

The Kobayashi group devised a two-step synthesis of 7-aryl-6,7-dihydrothieno[2,3- ]pyrazines. Aryl(3-chloropyrazin-2-yl)methanones were treated with methylene triphenylphosphorane under Wittig reaction conditions to furnish alkene 155, which in turn is stirred with aqueous sodium hydrosulfide, affording 6,7-dihydro-7-arylthieno[2,3-f)]pyrazine 156 (Scheme 77) (13HTC1507). Subsequent dehydrogenation with a catalytic amount of 10% palladium on carbon provided the desired 7-aryl-6,7-dihydro thieno [2,3-b] pyrazine 157. 

Thieno[2,3-e]azaborine-6-carboxylic acid, 1,2-dihydro-2-phenyl-3-(2-thienyl)-methyl ester... 

Thieno[ 1,2,3]diazaborines, dihydro-bromination, 1, 656 deuteration, 1, 658 iodination, 1, 656 nitration, 1, 656 nucleophilic substitution copper-promoted, 1, 658 Thienodiazepines synthesis, 7, 595 Thieno[ 1,2]diazepines synthesis, 7, 598 Thieno[2,3-d][l, 2]diazepines synthesis, 4, 749 Thieno[3,2-d][l,2]diazepines synthesis, 4, 749 Thieno[ 1,3]diazepines synthesis, 7, 607 Thieno[ 1,4]diazepinones as anticonvulsants, 1, 170 Thieno[3,4-d][l,3]dioxol-2-one, 4,6-diphenyl-... 

Thieno[3,4-d]isothiazole, 2,3-dihydro-3-oxo-1,1-dioxide, 6, 989 biological activity, 6, 1024 Thieno[2,3-c]isothiazole-3-carboxylic acid synthesis, 6, 1023... 

Thieno[2,3-d]isoxazoline, 4,4-dioxo-3-(2,4,6-trimethylphenyl)-3 a,6a-dihydro-synthesis, 6, 998... 

Thieno[3,4-d]oxazole-3a(4H)-carboxylic acid, dihydro-2-methyl-synthesis, 6, 1020 Thieno[2,3-d Joxazoles synthesis, 6, 990 Thieno[3,2-g]pteridine structure, 3, 284 lH-Thieno[3,4-c]pyran-2-ones synthesis, 4, 1032 Thienopyrazines synthesis, 4, 1022-1024 Thieno[2,3-6]pyrazines, 4, 1023 electrophilic substitution, 4, 1024 Thieno[3,4-6]pyrazines, 4, 1024 Thieno[3,4-c]pyrazole, 4,6-dihydro-3-hydroxy-carbamates... 

Thieno[3,2-c]pyridine-4(5H)-thione, 6,7-dihydro-synthesis, 4, 762 Thieno[2,3-c]pyridin-4-ones synthesis, 4, 1007, 1008 Thieno[2,3-c]pyridin-7-ones synthesis, 4, 1007 Thieno[3,2-c]pyridin-7-ones synthesis, 4, 1007... 

Thieno[2,3-d ]pyrimidin-4(3 H) -one, 3-methyl-synthesis, 4, 1017 Thieno[2,3-d ]pyrimidin-4-ones synthesis, 4, 1017, 1018, 1022 Thieno[2,3-6]pyrrole, 5-aryl-synthesis, 6, 1009 Thieno[2,3-6]pyrrole, N-benzyl- H NMR, 4, 1042 UV spectra, 4, 1044 Thieno[2,3-c]pyrrole, N-ethyl-UV spectra, 4, 1044 Thieno[3,2-6]pyrrole, 5-aryl-synthesis, 6, 1009 Thieno[3,2-6]pyrrole, N-benzyl- H NMR, 4, 1041, 1042 lithiation, 4, 1051 UV spectra, 4, 1044 Thieno[3,2-6]pyrrole, 2,3-dihydro-desulfurization, 6, 984 oxidation, 6, 981... 

Thieno[3,2-6]pyrrole, 5-ethoxycarbonyl-acylation, 4, 1050 synthesis, 4, 1070 Thieno[3,4-c]pyrrole, 5,6-dihydro-synthesis, 6, 987... 

Chemical Name 5-(o-Chlorophenyl)-7-ethyl-1,3-dihydro-1-methyl-1H-thieno[2,3-e] -1,4-di-azepin-2-one... 

To a solution of 10 g of 2-N-methyl-aminoacetamido-3-o-chlorobenzoyl-5-ethylthiophene in 50 ml of pyridine are added 20 ml of benzene and 1.9 g of acetic acid. The resulting mixture is refluxed with stirring for 10 hours in a flask provided with a water-removing adaptor. The reaction mixture is concentrated, and the residue is extracted with chloroform. The chloroform layer is washed with water and then with a sodium hydrogen carbonate solution, then dried over magnesium sulfate. The chloroform is distilled off under reduced pressure, and toluene is added to the residue. Thus is precipitated white crystalline-5-o-chloropheny -7-ethyl-1 -methyi-1,2-dihydro-3H-thieno-[2,3-e] [ 1,4] diazepin-2-one, MP 105°C to 106°C. 

N. A-Diethyl-2.3-dihydro-8//-thieno[2,3-r/]azcpin-7-amine (20), which is obtained in 49 % yield by photolysis of 6-azido-2,3-dihydrothiophene in a mixture of diethylamine and tetrahydro-furan. on treatment with bromine yields the fully unsaturated derivative 21.1,4... 

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