Synthesis of 1-substituted-3,3-dimethyl-3,4-dihydroisoquinolines

The Ritter reaction between -substituted propionitriles and dimethylbenzylcarbinols gives 3,3-dimethyl-3,4-dihydroisoquinolines containing substituents in the 1-position corresponding to those in the starting nitrile.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 657–659, May, 1991.     

Synthesis of 6-Aryl-3,3-dimethyl-5-phenyl-2,3,5,6-tetrahydropyran-2,4-diones

Zinc enolates obtained from methyl 4-bromo-2,2-dimethyl-3-oxo-4-phenylbutanoates and zinc react with aromatic aldehydes to form 6-aryl-3,3-dimethyl-5-phenyl-2,3,5,6-tetrahydropyran-2,4-diones as a single geometric isomer.     

Synthesis of 7- (or 6-)hydroxy derivatives of 3,3-dimethyl-3,4-dihydroisoquinoline

When treated with cyanoacetic ester in conc. H₂SO₄ 1-(4-hydroxy-3-methoxyphenyl)- and 1-(3-hydroxy-4-methoxyphenyl)-2-methylpropan-1-ol form ethyl 7-hydroxy-6-methoxy-3,3-dimethyl(or 6-hydroxy-7-methoxy- 3,3-dimethyl)-1,2,3,4-tetrahydroisoquinolylidene-1-acetate. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 421-425, March, 2009.     

Synthesis of the S-cis-oxime of 3,3-dimethyl-3,4-dihydroisoquinolyl-1-carbaldehyde

The reaction of 1-(2-hydroxy-2-trifluoromethyl-3,3,3-trifluoropropyl)-3,3-dimethyl-3,4-dihydroisoquinoline with a nitrosylating mixture gave only the S-cis-oxime of 3,3-dimethyl-3,4-dihydroisoquinolyl-1-carbaldehyde.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2136–2137, September, 1990.     

3,4-二氢-1H-2-苯并吡喃衍生物化合成

3,4-二氢-1 H-2-苯并吡喃也俗称异色满(isochroman)。近年来,将该类化合物引入到药物合成中的研兖引起了人们的兴趣。虽然,已经合成出许多具有镇痛、降血压、抗组胺。和抗肿瘤等药理活性的3,4-二氢-1 H-2-苯并吡喃类化物,合但大都为异色满环上的1,3,4位取代衍生物或者螺环化合物,关于并杂环合成方面的研究至今不多见,作者前     

A Solution-Phase Parallel Synthesis of 5-Substituted 3,6-Dihydro-7H-1,2,3-triazolo[4,5-d]pyrimidin-7-ones

5‐Substituted 7H‐1,2,3‐triazolo[4,5‐d]pyrimidin‐7‐ones ( 4 ) were rapidly prepared by a solution‐phase parallel synthetic method, which includes aza‐Wittig reaction of iminophosphorane ( 1 ) with phenyl isocynate to give carbodiimide ( 2 ) and subsequent reaction of 2 with various amine and alcohols in the presence of catalytic amount of sodium alkoxide in a parallel fashion.     

Synthesis of 7-Fluoro-9,10-Dihydro-2-Phenanthrylalkanoic Acids

The syntheses of 2-fluoro-9,10-dihydro-2-phenanthrylacetic acid (1) and 4-(7-fluoro-9,10-dihydro-2-phenanthryl)-4-oxobutanoic acid (2) from 9,10-dihydro-2-nitrophenanthrene (4) are described.     

Facile synthesis of 3,4-dihydro-4,4-dimethyl-2H-pyran-2-one via palladium catalyzed terminal oxidation of 3,3-dimethyl-4-pentenoates

Selective terminal oxidation of 3,3-dimethyl-4-pentenoates does occur under chloride-free Wacker conditions [Pd(OAc)₂/O₂] in AcOH to give 5-acetoxy-3,3-dimethyl-4-pentenoates (7) and their analogues (2, 8) in good yields. Successive cyclization of 7 and 8 at vapor phase pyrolysis on SiO₂ affords 3,4-dihydro-4,4-dimethyl-2H-pyran-2-one (1).     

Reaction between Dichlorophosphines and Azoalkenes: A General Synthesis of 3,4-Dihydro-2H-1,2,3-diazaphosphole Derivatives

The reaction between dichlorophosphines and azoalkenes provides a smooth method for the preparation of 3,4-dihydro-2H-1,2,3-diazaphosphole-3-oxides. When R¹ ≠ H, the cis: trans ratio is strongly dependent on the nature of the R⁴ substituent. Compounds arising from phenylazoalkenes are stable for several months, whereas compounds arising from methylazoalkenes undergo modifications during silica gel chromatography. Trichlorosilane reduction of these oxides gives the corresponding phosphines with retention of configuration. In some cases, this process competes with stereomutation of the starting phosphine oxide. Aryl-substituted phosphines are much more stable than the corresponding alkyl-substituted phosphines.     

Synthesis and Structure of 3,4-Dihydro-4-phenyl-1,5-benzodioxepin-2-ones

Baeyer-Villiger rearrangement of substituted flavanones using MCPBA affords ring-expanded products, shown by NMR spectroscopy to be the corresponding 3,4-dihydro-4-phenyl-1,5-benzodioxepin-2-ones.     

5-羟基-3,4-二氢异喹啉-1-酮的合成

以异喹啉为起始原料,经成盐、磺化得异喹啉-5-磺酸(3),3与熔融的氢氧化钠和氢氧化钾反应得1,5-二羟基异喹啉(4),以5%Pd-C为催化剂还原4得5-羟基-3,4-二氢异喹啉-1-酮(1),总收率47.6%。1的结构经1H NMR和MS确证。     

Microwave Induced Synthesis of 3,4-Dihydro-2H-pyran-2-carboxaldehyde: A Versatile Linker for Solid Phase Combinatorial Library

Procedures for the dimerization of acrolein to form 3,4-dihydro-2H-pyran-2-carboxaldehyde by microwave induced synthesis have been developed. Significant rate-enhancement and yield increase were observed. 3,4-Dihydro-2H-pyran-2-carboxaldehyde was obtained in 91% yield under microwave irradiation for 5 minutes instead of 39% yield by reacting at 190 °C for 40 min or at 160 °C for 4 hr.     

Crystal and molecular structure of cyclic sulfoxides: 2-cyano-2-ethoxycarbonyl-3,6-dihydro-4,5-dimethyl-2H-thiapyran 1-oxide and 2-phenyl-2-methoxycarbonyl-3,6-dihydro-2H-thiapyran 1-oxide

Crystal and molecular structures of the title compounds 1b and 1c have been determined by the X-ray method. Crystals of 1b are monoclinic, space group P2₁/c, and crystals of 1c are orthorhombic, space group P2₁2₁2₁. The sulfinyl oxygen atom and the alkoxycarbonyl group in both compounds are trans oriented, and the six-membered rings adopt a sofa conformation. The differences between conformation, bond lengths, and angles in the compounds investigated are discussed. © John Wiley & Sons, Inc.     

An Efficient Synthesis of 4,5-Dihydro-3(2H)-pyridazinone Derivatives

Reaction of hydrazine with 5-(2-aryl-2-oxo-ethan-1-yl)-5-R Meldrum's acids 3 gives 4,6-disubstituted 4,5-dihydropyridazin-3(2H)-ones 4 at room temperature. The method is simple and the yield is good. The production of the starting material 3 also is discussed.     

Synthesis and studies on spectral behaviour and molecular dynamics of 7-Aryl-4,5-Dihydro-2-Oxo-3H,8H-Furo[3,4-b] [1,4]diazepines

A new series of 7-aryl-4,5-dmydro-2-oxo-3H,8H-furo[3,4-b][1,4] diazepines were prepared. Their ^lH nmr spectra have been interpreted in terms of the interconversion of two pseudo-boat conformers. Molecular-dynamics simulations at different temperatures on this type of compounds revealed a very small energy difference between these two conformers.     

Synthesis and biological screening of 7-hydroxy-4-methyl-2H-chromen-2-one, 7-hydroxy-4,5-dimethyl-2H-chromen-2-one and their some derivatives

7-Hydroxy-4-methyl-2H-chromen-2-one (2), 7-hydroxy-4,5-dimethyl-2H-chromen-2-one (15) and their some derivatives were synthesized for exploring selected biological screening. The compounds 9 and 13 had shown high degree of cytotoxic activity. Three compound 9, 10 and 13 showed high degree of bactericidal activity amongst the present series.     

Studies on β-Enaminonitriles: A one-pot Regiospecific Synthesis of Polysubstituted 3,4-Dihydro-2(1H)-Pyridones

Reaction of α, β-unsaturated acid chlorides with primary enaminonitriles in presence of triethylamine affords, under very mild conditions, a simple and highly efficient regiospecific synthesis of polysubstituted 3,4-dihydro-2(1H)-pyridones.