کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1347910 980330 2012 15 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Absolute configuration assignment of 3-indolylacetate esters
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی معدنی
پیش نمایش صفحه اول مقاله
Absolute configuration assignment of 3-indolylacetate esters
چکیده انگلیسی

Herein we describe a straightforward method for the determination of the absolute configuration of 3-indolyl(bromo)acetate 7, 3-indolyl(alkoxy)acetates 8a–f and 3-indolyl(amino)acetate 8g, based on 1H NMR spectral analysis. The conformational preferences for two diastereomeric esters were calculated by DFT, which matched very well with the experimental results. X-ray diffraction analysis allowed us to validate the methodology, and independent absolute configuration evidence was obtained by vibrational circular dichroism.

Absolute configuration assignment by 1H NMR and VCD.Figure optionsDownload as PowerPoint slide

(1R,2S,5R)-2-Isopropyl-5-methylcyclohexyl 2-(1H-indol-3-yl)acetateC20H27NO2ee >98% (by 1H NMR)[α]D20=-68.8 (c 1.6, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (10R,11S,14R)

(R)-sec-Butyl 2-(1H-indol-3-yl)acetateC14H17NO2ee >98% (by 1H NMR)[α]D20=-13.3 (c 0.60, EtOH)Source of chirality: (R)-(−)-2-ButanolAbsolute configuration: (10R)

Methyl 3-(2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC22H29NO4ee >98% (by 1H NMR)[α]D20=-51.9 (c 1.5, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (10R,11S,14R)

(R)-Methyl 3-(2-sec-butoxy-2-oxoethyl)-1H-indole-1-carboxylateC16H19NO4ee >98% (by 1H NMR)[α]D20=-18.3 (c 1.2, EtOH)Source of chirality: (R)-(−)-2-ButanolAbsolute configuration: (10R)

tert-Butyl 3-(2-((1R,2R,5S)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC25H35NO4ee > 98% (by 1H NMR)[α]D20=-40.8 (c 1.2, EtOH)Source of chirality: (1R,2S,5R)-(-)-MentholAbsolute configuration: (10R,11S,14R)

Methyl 2,6-dibromo-3-((S)-1-bromo-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC22H26Br3NO4ee >98% (by 1H NMR)[α]D20=-5.0 (c 0.5, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8S,10R,11S,14R)

Methyl 2,6-dibromo-3-((R)-1-bromo-2-((1R,2R,5S)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC22H26Br3NO4ee >98% (by 1H NMR)[α]D20=-2.0 (c 0.6, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8R,10R,11S,14R)

Methyl 3-((S)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC23H31NO5ee >98% (by 1H NMR)[α]D20=-16.0 (c 1.3, EtOH)Source of chirality: (1R,2S,5R)-(-)-MentholAbsolute configuration: (8S,10R,11S,14R)

Methyl 3-((R)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC23H31NO5ee > 98% (by 1H NMR)[α]D20=-102.9 (c 1.6, EtOH)Source of chirality: (1R,2S,5R)-(-)-MentholAbsolute configuration: (8R,10R,11S,14R)

Methyl 3-((S)-1-ethoxy-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC24H33NO5ee >98% (by 1H NMR)[α]D20=-18.9 (c 1.6, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8S,10R,11S,14R)

Methyl 3-((R)-1-ethoxy-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC24H33NO5ee >98% (by 1H NMR)[α]D20=-70.8 (c 1.2, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8R,10R,11S,14R)

Methyl 3-((S)-1-isopropoxy-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC25H35NO5ee >98% (by 1H NMR)[α]D20=-14.8 (c 2.2, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8S,10R,11S,14R)

Methyl 3-((R)-1-isopropoxy-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-2-oxoethyl)-1H-indole-1-carboxylateC25H35NO5ee >98% (by 1H NMR)[α]D20=-83.2 (c 2.5, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8R,10R,11S,14R)

Methyl 3-((S)-2-sec-butoxy-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC17H21NO5ee >98% (by 1H NMR)[α]D20=+41.3 (c 0.8, EtOH)Source of chirality: (R)-(−)-2-ButanolAbsolute configuration: (8S,10R)

Methyl 3-((R)-2-sec-butoxy-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC17H21NO5ee >98% (by 1H NMR)[α]D20=-51.7 (c 1.2, EtOH)Source of chirality: (R)-(−)-2-ButanolAbsolute configuration: (8R,10R)

tert-Butyl 3-((S)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC26H37NO5ee > 98% (by 1H NMR)[α]D20=-12.5 (c = 1.2, EtOH).Source of chirality: (1R,2S,5R)-(-)-MentholAbsolute configuration: (8S,10R,11S,14R)

tert-Butyl 3-((R)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC26H37NO5ee >98% (by 1H NMR)[α]D20=-88.75 (c 0.8, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8R,10R,11S,14R)

Methyl 2,6-dibromo-3-((S)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC23H29Br2NO5ee > 98% (by 1H NMR)[α]D20=-96.1 (c 0.8, EtOH)Source of chirality: (1R,2S,5R)-(-)-MentholAbsolute configuration: (8S,10R,11S,14R)

Methyl 2,6-dibromo-3-((R)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-methoxy-2-oxoethyl)-1H-indole-1-carboxylateC23H29Br2NO5ee >98% (by 1H NMR)[α]D20=-5.0 (c 0.8, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8R,10R,11S,14R)

Methyl 3-((S)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-(methylamino)-2-oxoethyl)-1H-indole-1-carboxylateC23H32N2O4ee >98% (by 1H NMR)[α]D20=-10.9 (c 1.27, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8S,10R,11S,14R)

Methyl 3-((R)-2-((1R,2S,5R)-2-isopropyl-5-methylcyclohexyloxy)-1-(methylamino)-2-oxoethyl)-1H-indole-1-carboxylateC23H32N2O4ee >98% (by 1H NMR)[α]D20=-87.0 (c 1.21, EtOH)Source of chirality: (1R,2S,5R)-(−)-MentholAbsolute configuration: (8R,10R,11S,14R)

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Tetrahedron: Asymmetry - Volume 23, Issue 17, 15 September 2012, Pages 1279–1293
نویسندگان
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