An efficient synthesis of 4-alkyl-2(1H)-quinazolinones and 4-alkyl-2-chloroquinazolines from 1-(2-alkynylphenyl)ureas

An efficient synthesis of 4-alkyl-2(1H)-quinazolinones has been achieved by cyclization of 1-(2-alkynylphenyl)ureas (2 R₂ = alkyl) in dichloroethane catalyzed by TfOH. In the case of aryl substitution (2 R₂ = aryl), a mixture of quinazolinone tautomers is obtained in dichloroethane with TFA as co-solvent. Chlorination of the resulting mixture affords 4-alkyl-2-chloro-quinazolines as sole products.     

Crystal structure of tris(2-pyridylthio-2-pyridinium)pentaisothiocyanato-dioxouranate(VI)

Summary The crystal structure of [DPSH] ₃ ⁺ [UO₂[NCS)₅]^3– (DPSH = 2 pyridylthio-2-pyridinium) has been determined by standard methods using diffractometer data. Crystals are monoclinic, space groupP2₁/a, witha=33.16 (3),b=16.68(2),c=7.85(1) Å, and=97.3(1); D_c=1.65 g · cm^–3 for Z=4. The structure has been refined to R=5.8% by least squares methods. Five thiocyanate groups are equatorially bonded to the linear uranyl group. The mean of the five U-N, N-C, and C-S bond distances are 2.45, 1.17, and 1.59 Å respectively. The protonated DPS molecules have the N,N-inside conformations.     

Synthesis of some 2-alkyl-4-quinolone and 2-alkyl-4-methoxyquinoline alkaloids

Acid-catalyzed condensation of a series of 3-oxoalkanoic acid esters with aniline affords the corresponding 2-alkyl-4-quinolones in good yield. Treatment of these compounds with methyl iodide affords 2-alkyl-4-methoxyquinolines and 2-alkyl-N-methylquinolones. Three of the compounds are naturally-occurring alkaloids which are synthesized here for the first time.     

(2-己基-1,3-二氧杂戊环-4)甲烷-1-吡啶盐的合成及其表面活性

以脂肪醛、环氧溴丙烷、吡啶为原料,在三氟化硼乙醚的催化下,通过缩合、N-烷基化反应合成了新型含吡啶环1,3-二氧杂环戊烷的单阳离子表面活性剂——(2-己基-1,3-二氧杂戊环-4)甲烷-1-吡啶盐(2),其结构经1H NMR和IR表征.表面活性测试结果表明,2在20℃时临界胶束浓度为4.5×10-3mol·L-1,Krafft点低于20℃,泡沫稳定性72.7％,乳化性2 min.     

四-（4-吡啶基）卟啉二酸聚集体的共振拉曼光谱

研究了近激子吸收带激发下四-（4-吡啶基）卟啉二酸（H8TPyP^6＋）聚集体的共振拉曼光谱。测量了H8TPyP^6＋单体和聚集体的紫外可见吸收谱和共振光散射光谱．在氘代位移的基础上结合相关体系振动光谱研究,对测得的H8TPyP^6＋单体和聚集体的拉曼谱带进行了指认．聚集体的形成导致H8TPyP^6＋的卟啉环CC／CN面内伸缩振动向低波数方向位移2-6cm^-1,而卟啉环鞍形面外振动带向高波数方向位移12cm^-1．基于拉曼谱带的强度和频率变化分析了聚集引起的H8TPyP^6＋分了内结构变化和分子间氢键作用．     

(E)-1-alkyl-4-

(E)-1-Alkyl-4-[2-(alkylsulfonyl)-1-ethenyl]pyridinium salts were synthesized in two steps. These sulfones were stable at pH 7.3 and underwent a nucleophilic vinylic substitution (S(N)V) with mercaptans, including thiouracile, to give the corresponding 4-(thiovinyl)-pyridinium salts. The X-ray diffraction structure of (E)-1-methyl-4-[2-(ethylsulfanyl)-1-ethenyl]pyridinium iodide indicated conjugation of the sulfur with the pyridinium ring. (Z)-1-Methyl-4-[2-(methylsulfanyl)-1-ethenyl]pyridinium iodide, prepared from the corresponding thioether by reaction with methyl iodide in diethyl ether, underwent isomerization to the E isomer in a first-order reaction in deuterated [D6]DMSO with an activation energy of 14 kcalmol(-1). At pH 7, the (E)-1-methyl-4-[2-(methylsulfonyl)-1-ethenyl]pyridinium iodide (19) reacted specifically with thiols. The reaction of this sulfone with glutathione in a TES buffer at pH 7 was a second-order reaction (k = 4,100 M(-1)s(-1) at 30 degrees C) and gave the corresponding substitution product with an intense long wavelength absorption band (lambdamax=360 nm, epsilon = 27,500 M(-1)cm(-1)). The modification of different enzymes of known structure with 19 showed the high selectivity of this reagent towards thiol groups and its usefulness in the quantitative determination of free thiol groups in proteins.     

Vibrational spectra and structure of N-tozyl(4-dimethylamino)-pyridinium salts

Normal vibrations and absorption band forms for N-tozyl(4-dimethylamino)pyridinium cation have been calculated in the harmonic approximation. On the basis of this calculation complete interpretation for N-tozyl(4-dimethylamino)pyridinium salts with Cl⁻, Br⁻, ClO⁻₄ and BPh⁻₄ anions has been carried out; several conclusions are made concerning the structure of the compounds under investigations.     

Synthesis of 4-thiocarbamoyl-5-aminopyrazoles

Aryl and t-butylhydrazines react with 2-cyano-3-ethoxythiocrotonamide affording 2-cyano-3-aryl-t-butylhy-drazinothiocrotonamides. These intermediates can be easily cyclized to 4-thiocarbamoyl-5-aminopyrazoles by heating a few minutes in a strong base. Alkylhydrazines react with 2-cyano-3-ethoxythiocrotonamide yielding directly a mixture of the cyclized compounds 4-cyano-5-aminopyrazoles and 4-thiocarbamoyl-5-aminopyr-azoles.     

Bis（4-chloro-2-cyclohexylimino methylphenolate）-two Thiocyanation Cadmium

1 INTRODUCTION Schiff base compounds have been of great interest for many years. These compounds are important systems in asymmetric catalysis and their transition metal complexes can often mimic biological sites, so they are of great significance as enzyme models. Their five- and six-coordinate complexes can disp- lay a variety of structural and magnetic properties. Complexes of d10 metal ion, such as cadmium (II), have aroused great attention since they are involved in many biological …