延胡索乙素的晶体及分子结构

本文报导用直接法测定延胡索乙素游离碱的晶体结构。晶体所属的空间群为P2_12_12_1,每个单胞中含有四个分子,晶胞参数为a=22.296,b=11.795,c=7·452。用块对角矩阵最小二乘方对全部非氢原子坐标及其各向异性温度因子,对氢原子坐标及其各向同性温度因子进行修正,最后R因子为0.045。本文对于分子的某些结构特征作了讨论。     

The Absolute Configuration of 1-Methylindane

It is shown unequivocally by chemical correlations (cf. Schemes 1--3) and Raman optical activity spectra (cf. Fig. 1 and 2) that the (R)-configuration has to be attributed to (+)-1-methylindane ((+)- 1 ). This is in contradiction to an earlier assignment of the (R)-configuration to (?)- 1 [2] which was based on the (R)-configuration of (+)-indane-1-carboxylic acid ( 3 ) [11].     

Synthesis, Crystal Structure and AbsoluteConfiguration of （＋）-O-Phenyl Cyclophosphorodiamidate

The title compound, ( )-O-phenyl cyclophosphorodiamidate (C28H33N202P, Mr=460.53), has been synthesized and characterized by 31p NMR, 1H NMR and elemental analysis. X-ray diffraction analysis at 273(2) K indicates that it belongs to orthorhombic system, space group P212121 with a=11.518(4), b=13.449(4), c=16.539(5)A, V=2562(1)A3, Z=4, Dc=1.194g/cm3, F(000)=984 and μ(MoKα)=0.134mm-l. The structure parameters were refined by full-matrix least-squares on F2 to R=0.0459 and wR=0.0640. The flack χ parameter is 0.03(10), and the absolute configuration of the phosphorus atom in the title compound is S.     

(+)-O-萘基环状磷酰二胺酯的合成、晶体结构及绝对构型

合成了目标化合物(+)-O-萘基环状磷酰二胺酯,其结构由¹HNMR,³¹PNMR及元素分析确定,并在273K下进行了X射线衍射晶体结构分析.该化合物晶体属正交晶系,P2₁2₁2₁空间群,晶胞参数a=1.0028(4)nm,b=1.1406(4)nm,c=2.4455(8)nm,V=2.7971(18)nm₃,Z=4,Dc=1.212g/cm³,F(000)=1088,μ=0.129mm^-1.晶体的结构收敛最终偏离因子R和wR分别为0.0585和0.0827.Flackx参数为0.03(12).目标化合物中磷原子的绝对构型为S.     

Absolute Configuration of Gilmaniellin

The absolute configuration of dechlorogilmaniellin ( 2 ) could be determined from its chiroptical data by applying coupled-oscillator theory to the CD couplet around 272 nm and from the sign of its n →π^* Cotton effect. Gilmaniellin ( 1 ) has the same absolute configuration.     

Absolute Configuration of Actinioerythrin

The CD. correlation of (3 S, 3′S)-and (3 R, 3′R)-actinioerythrol diacetate, obtained by total synthesis from β-ionone, with actinioerythrin isolated from the sea anemone Actinia equina L. shows that the natural compound has the (3 S, 3′S)-configuration.     

Absolute Configuration and Crystal Structure of a Phosphonate Analogue of Tyrosine Produced by Actinomycetes

Abstract

Levorotatory 1-amino-2-(4-hydroxyphenyl)ethylphosphonic acid (TyrP) of unknown configuration is a part of hypotensive tri-peptides produced by Actinomycetes¹ and is the only 1-aminoalkane phosphonate found so far in living organisms. Nitration of enantiomers of PheP followed by reduction of the p-nitro group and diazotization yielded enantiomers of TyrP of specific rotations +67 and ?67° (c.0.9;1n HCl). Single crystal X-ray analysis showed S configuration for dextrorotatory TyrP. Thus, natural levorotatory TyrP has the R configuration and belongs to the L series of aminoacids.     

Conformational Dynamics and Absolute Configuration of Sawaranin

Chemistry of Natural Compounds - Butyrolactone 1 was isolated from the EtOAc fraction of the EtOH extract of the aerial part of Geranium charlesii (Aitch. & Hemsl.) Vved. The configurations...     

Absolute Configuration of the Levocloperastine Fendizoate

Crystal structure of the levocloperastine fendizoate (C80H76Cl2N2O10, C20H25ClNO+· C20H13O4-) has been determined by single-crystal X-ray diffraction. The crystal is of triclinic system, space group P1 with a = 10.1059(18), b = 11.957(2), c = 15.383(3) , α = 104.666(2), β = 90.9700(10), γ = 110.744(2)°, Z = 1, V = 1670.0(5) 3, Dc = 1.289 g/cm3, F(000) = 684, μ(MoKα) = 0.161 mm-1, Mr = 1296.33, the final R = 0.0343 and wR = 0.0676. The cations and anions are linked by the COO…NH hydrogen bonds of 2.709(3) and 2.690(3)  and COO…OH hydrogen bonds of 2.632(3) and 2.631(3) . The configuration of the only one chiral carbon atom in this compound is R(rectus).     

物质的绝对构型与旋光性的关系

对物质的绝对构型与旋光方向关系的有关理论进行了简单介绍。     

(+)-Cannabispirenone-A: Synthesis and Absolute Configuration

An efficient asymmetric synthesis of cannabispirenone-A (la) has been accomplished. The absolute configuration of the (+)-(la) is assigned as R. The magnitude of rotation calls the optical purity of the natural product into question.