Stereochemical studies. Part 31. Ring closure reaction of cis- and trans-2-(bromomethyl)cycloalkylamines

1979 ◽  
pp. 1770-1773 ◽  
Author(s):  
György Göndös ◽  
Kornélia L. Láng ◽  
Andrea Szeghy ◽  
György Dombi ◽  
Gábor Bernáth
Keyword(s):  
Ring Closure ◽  
Cis And Trans

PYRAZOLINES: V. RING CLOSURE TO OXYGEN IN THE PYROLYSIS OF 3-ACETYL-Δ1-PYRAZOLINES

1965 ◽  
Vol 43 (5) ◽  
pp. 1398-1406 ◽  
Author(s):  
Donald E. McGreer ◽  
Norman W. K. Chiu ◽  
Magnus G. Vinje
Keyword(s):  
Ring Closure ◽  
Product Analysis ◽  
Pyrolysis Reaction ◽  
A Minor ◽  
Cis And Trans

The pyrolysis of 3-methyl-3-acetyl-Δ1-pyrazoline (IV) and cis- and trans-3,5-dimethyl-3-acetyl-Δ1-pyrazoline (V and VI) has been studied. Pyrolysis of IV gave 2,3-dimethyl-4,5-dihydrofuran (XI) as a minor product, indicating some ring closure to oxygen in these reactions. Pyrolysis of V gave 2,3,5-trimethyl-4,5-dihydrofuran (XVII) as 23% of the product, whereas VI yielded only a trace of XVII. This fact and other differences in the product analysis from isomers V and VI are discussed in terms of the possible mechanism for the pyrolysis reaction.

ChemInform Abstract: RING CLOSURE REACTION OF CIS- AND TRANS-2-(BROMOMETHYL)CYCLOALKYLAMINES

1980 ◽  
Vol 11 (35) ◽  
Author(s):  
GY. GOENDOES ◽  
K. L. LANG ◽  
A. SZEGHY ◽  
GY. DOMBI ◽  
G. BERNATH
Keyword(s):  
Ring Closure ◽  
Cis And Trans

OXIDATION OF CIS- AND TRANS-1-AMINO-2,6-DIPHENYLPIPERIDINE. A NEW TYPE OF RING CLOSURE

1957 ◽  
Vol 79 (6) ◽  
pp. 1510-1511
Author(s):  
C. G. Overberger ◽  
Joseph G. Lombardino ◽  
Richard G. Hiskey
Keyword(s):  
Ring Closure ◽  
New Type ◽  
Cis And Trans

The Atetidine Ring-closure Reaction of cis- and trans-2-(Bromomethyl)cycloalkylamines

Heterocycles ◽  
1978 ◽  
Vol 9 (10) ◽  
pp. 1519
Author(s):  
Gy. Göndös ◽  
K. L. Láng ◽  
G. Bernáth
Keyword(s):  
Ring Closure ◽  
Cis And Trans

ChemInform Abstract: STEREOCHEMICAL STUDIES. PART 31. RING CLOSURE REACTION OF CIS- AND TRANS-2-(BROMOMETHYL)CYCLOALKYLAMINES

1979 ◽  
Vol 10 (43) ◽  
Author(s):  
G. GOENDOES ◽  
K. L. LANG ◽  
A. SZEGHY ◽  
G. DOMBI ◽  
G. BERNATH
Keyword(s):  
Ring Closure ◽  
Cis And Trans

scholarly journals Stereoselective Synthesis and Antiproliferative Activity of Steviol-Based Diterpen Aminodiols

2019 ◽  
Vol 21 (1) ◽  
pp. 184
Author(s):  
Dániel Ozsvár ◽  
Viktória Nagy ◽  
István Zupkó ◽  
Zsolt Szakonyi
Keyword(s):  
Antiproliferative Activity ◽  
Ring Opening ◽  
Stereoselective Synthesis ◽  
Click Reaction ◽  
Substituent Effects ◽  
Ring Closure ◽  
Secondary Amines ◽  
Structure Activity ◽  
Cis And Trans ◽  
Benzyl Substituent

A library of steviol-based trifunctional chiral ligands was developed from commercially available natural stevisoide and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. The key intermediate steviol methyl ester was prepared according to literature procedure. Depending on the epoxidation process, both cis- and trans-epoxyalcohols were obtained. Subsequent oxirane ring opening with primary and secondary amines afforded 3-amino-1,2-diols. The ring opening with sodium azide followed by a “click” reaction with alkynes resulted in dihydroxytriazoles. The regioselective ring closure of N-substituted aminodiols with formaldehyde was also investigated. The resulting steviol-type aminodiols were tested against a panel of human adherent cancer cell lines (A2780, SiHa, HeLa, and MDA-MB-231). It was consistently found that the N-benzyl substituent is an essential part within the molecule and the ring closure towards N-benzyl substituted oxazolidine ring system increased the antiproliferative activity to a level comparable with that of cisplatine. In addition, structure–activity relationships were examined by assessing substituent effects on the aminodiol systems.

Stereospecific reactions of cis- and trans-3-Aminochroman-4-ols

1977 ◽  
Vol 30 (10) ◽  
pp. 2205 ◽  
Author(s):  
BV Lap ◽  
LR Williams
Keyword(s):  
Amino Alcohol ◽  
Nitrous Acid ◽  
Potassium Hydroxide ◽  
Amino Alcohols ◽  
Ring Closure ◽  
Stereospecific Reactions ◽  
Cyclic Amide ◽  
Cis And Trans ◽  
Effect Ring ◽  
Chemical Evidence

Stereospecific reactions of epimeric 3-amino-6-methylchroman-4-ols (1 and 2; R = Me) have provided chemical evidence for their configuration and have led us to reverse the configurations that we had assigned previously to the 6-bromo analogues on the basis of N.M.R. data. ��� The 2-chloro-N-(4-hydroxy-6-methylchroman-3-yl)acetamides (3) and (4) were treated with potassium hydroxide in ethanol in an attempt to effect ring closure. The cis-chloroacetamide (4) gave a cyclic amide (5) while the trans-chloroacetamide (3) reacted with solvent to form the trans-3-ethoxyacetamidochroman-4-ol (6). ��� The configurations of the amino alcohols were confirmed by a study of their reactions with nitrous acid where deamination of the cis-amino alcohol gave the chroman-4-one (9) while the trans-amino alcohol gave a trans-diol (10) by an epoxide intermediate.

A Stereochemical and Kinetic Study of the Conversion of Methyl Cyclopropyl Ketones to 4,5-Dihydrofurans

1973 ◽  
Vol 51 (10) ◽  
pp. 1487-1493 ◽  
Author(s):  
Donald Edward McGreer ◽  
James William McKinley
Keyword(s):  
Kinetic Study ◽  
Ring Opening ◽  
Photochemical Reactions ◽  
Order Reaction ◽  
Ring Closure ◽  
Hydrogen Shift ◽  
First Order ◽  
Bond Rotation ◽  
Cyclopropyl Ketones ◽  
Cis And Trans

The thermal and photochemical conversion of (1R*,2R*,3S*), (1S*,2R*,3S*), and (1S*,2R*,3R*)-1-acetyl-1,2-dimethyl-3-phenylcyclopropane (1, 2, and 3) to cis- and trans-2,3,4-trimethyl-5-phenyl-4,5-dihydrofurans has been studied. Concurrent with this reaction is an equilibration of 1, 2, and 3, a thermal ring opening of 1 by a 1,5-hydrogen shift, and a cyclopropane-to-propene type reaction under the photochemical conditions. The dihydrofuran from 1 and 2 by the thermal and photochemical conditions is 97% trans- and 3% cis- corresponding to predominant retention at the migrating carbon. The dihydrofuran formed from 3 by the thermal and photochemical reaction is 85% cis- and 15% trans- again corresponding to predominant retention. A kinetic study of the rearrangement of 1-acetyl-1-methyl-2-phenylcyclopropane to 1,2-dimethyl-5-phenyl-4,5-dihydrofuran provides Ea of 48.1 kcal/mol and log A of 14.9 for this first order reaction in the temperature range of 255–288 °C.It is concluded that the thermal and photochemical reactions occur by a non-concerted process through a common 1,3-diradical intermediate in which bond rotation and ring closure steps are competitive.

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