Photochemistry of 5,5-Dimethyl-2(5H)-thiophenone

On irradiation (λ > 305 nm) in alcohols, 5,5-dimethyl-2(5H)-thiophenone ( 1b ) is converted to (E)-4-mercapto-4-methyl-2-pentenoates 8 . These esters undergo a consecutive light-induced reaction affording thiolanes when irradiated in the presence of alkenes, and either 2,3-dihydrothiophenes or 3-thiabicyclo[3.1.0]hexanes with alkynes.     

A calorimetric and computational study of the thermochemistry of halogenated 1-phenylpyrrole derivatives

The standard molar enthalpies of formation, in the crystalline phase, of three halogenated 1-phenylpyrrole derivatives, namely 1-(4-fluorophenyl)pyrrole, 1-(4-chlorophenyl)pyrrole, and 1-(4-iodophenyl)pyrrole were derived from the respective enthalpies of combustion, measured by rotating-bomb combustion calorimetry. Their enthalpies of sublimation, at T = 298.15 K, were obtained from the Knudsen mass-loss effusion technique. From these two experimental parameters, the standard molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, of 1-(4-fluorophenyl)pyrrole, 1-(4-chlorophenyl)pyrrole, and 1-(4-iodophenyl)pyrrole were calculated, respectively, as (26.2 ± 2.4) kJ · mol⁻¹, (196.2 ± 2.5) kJ · mol⁻¹, and (311.5 ± 2.4) kJ · mol⁻¹.The gas-phase enthalpies of formation of both fluorine and chlorine compounds were estimated by G3(MP2)//B3LYP computations. For the iodine compound, the B3LYP/6-311G(d):ECP46MDF approach was employed. Additionally, the DFT calculations were extended to estimate the enthalpy of formation of the bromine derivative, 1-(4-bromophenyl)pyrrole, performed at the B3LYP/6-311G(d) level of theory.     

Asymmetric Diels-Alder reactions with 5-menthyloxy-2-(5H)-furanone

A new class of chiral dienophiles, 5-alkoxy-2(5H)-furanones, has been developed. Both enantiomers of 5-menthyloxy-2(5H)-ftiranone are readily available in enantiomerically pure form, starting from furfural and d- or l-menthol. Excellent diastereoselectivities (d.e. β99%) are obtained in thermal Diels-Alder reactions with several cyclic and acyclic dienes. The use of silyl dienol ethers has resulted in new routes to enantiomerically pure cyclohexanones in a highly regioselective manner.     

Experimental study on the thermochemistry of 1-(2H)-phthalazinone and phthalhydrazide

The standard (p^° = 0.1 MPa) molar enthalpies of combustion of 1-(2H)-phthalazinone and phthalhydrazide, both in the solid phase, were measured at T = 298.15 K by static bomb calorimetry. Further, the standard molar enthalpies of sublimation, at T = 298.15 K, of these two phthalazine derivatives were derived from the Knudsen effusion technique. The combustion calorimetry results together with those obtained from the Knudsen effusion technique, were used to derive the standard molar enthalpies of formation, at T = 298.15 K, in the gaseous phase for 1-(2H)-phthalazinone and phthalhydrazide, respectively as, (79.1 ± 1.8) kJ · mol^?1 and ?(107.4 ± 2.4) kJ · mol^?1.     

A new synthesis of 5-methylene-2(5H)-furanone derivatives

5-methylene-2(5H)-furanone derivatives are easily obtained by treatment of tertiary 2-furylcarbinols with pyridinium dichromate in dimethylformamide solution. Through this procedure, a natural product, the thiophene lactone isolated from Chamaemelum Nobile L., has been synthesized.     

2(5H)-Furanone and 5-Hydroxy-2(5H)-furanone: Reactions and Syntheses Based on Them

Russian Journal of General Chemistry - This review summarizes the data on 2(5H)-furanone, 5-hydroxy-2(5H)-furanone, and some substituted hydrofuranones with respect to their poorly studied or...     

1,3-Dipolar Cycloaddition of Substituted Benzonitrile Oxide to 5-(R)-(l-Menthyloxy)-2(5H)-furanone

Isoxazoline compounds as key intermediates for construction of natural products have been developed very fast as an hot area in organic synthesis1. 5-(R)-(l-menthyloxy)- 2(5H)-furanone as a valuable chiral synthon has been recently studied for its high stereoselectivity in many reactions2. In this paper, we focused on its reactivity and regioselectivity of the 1,3-dipolar cycloaddition with the substituted benzonitrile oxide3 and several isoxazoline compounds were obtained and characterized…     

Modification of Synthesis of 3-Chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone(MX)

Addition of chlorine to methyl 3-(dichloromethyl)-4,4-dichlorocrotonate (1), a critical procedure in the total synthesis of the title compound MX, was modified by using novel catalysts. A minor modification in the purification of MX was also described.     

3-氯-4-二苄胺基-5-甲氧基-2(5H)-呋喃酮的合成与晶体结构

在THF溶液中合成了标题化合物3-氯-4-二苄胺基-5-甲氧基-2(5H)-呋喃酮,并用FT-IR、UV-Vis、1HNMR、13C NMR、MS、元素分析和X-射线衍射等进行了表征。结果表明此化合物属正交晶系,空间群为Pbca,晶胞参数为:a=15.891(16),b=11.126(11),c=19.778(19),α=β=γ=90°,V=3497(6)3,Z=8,Dc=1.306Mg/m3,μ=0.234 mm-1,F(000)=1440。在化合物的分子结构中,两个苯环几乎垂直于呋喃酮平面,且它们与呋喃酮平面的两面角分别为89.38°和88.19°。     

A Simple Synthesis of Brominated Analogues of 3-Chloro-4-(dichloromethyl)-5-hydroxy- 2(5H)-furanone (MX)

Abstract

Three brominated analogues of the highly mutagenic drinking water micropollutant 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) have been synthesized from MX by halogen exchange reaction.     

Molecular and crystal structure of 2-(N-benzyl-N-phenylhydrazinoethylidene)-3-(2H)-benzo[b]-thiophenone

X-ray structural analysis was used to determine the molecular and crystal structure of 2-(N-benzyl-N-phenylhydrazinoethylidene)-3-(2H)-benzo[b]thiophenone. The crystals are monoclinic, the space group isC2/c,a=16.022(6),b=11.202(3),c=22.111(4) Å, =81.08(3)°, and andZ=8. It was shown that the ability of hydrazones of a similar class to exhibit photochromic properties is a function of the steric stresses in the molecules and their confirmation.Institute of Chemical Physics in Chernogolovka, Russian Academy of Sciences, 142432 Chernogolovka. Translated fromIzvestiya Akademii Nauk, Seriya Khimicheskaya, No. 12, pp. 2805–2809, December, 1992.     

Asymmetric Photocatalyzed Addition of Cyclic Ammes to the Chiral 5-(l)-Menthyloxy-2(5H)-furanone

Inrecentyears,considerableattentionhasbeenfocusedonthesynthesisandpropertiesofchiralbutenolidesbecauseoftheirmultifunctionalnatureandversatilityonenantioselectivetransformationreactionsl'2.Despiteextensivestudiesofthisresearchworkonasymmetricreactionsbutlittleefforthasbeendevotedtowardsphotochemicalsynthesisofsomechiraly-substituted2-(SH)-furanones'.Amongthepreviouswork,thetertiaryammesusedinthephotocatalysedconjugateadditionsto5-substituted2(5H)foranoneswerethefirstexamples",andthesecondaryc…