The Action of Diazomethane upon Acyclic Sugar Derivatives. III.1A New Synthesis of Ketoses and of their Open Chain (keto) Acetates

1942 ◽  
Vol 64 (10) ◽  
pp. 2329-2331 ◽  
Author(s):  
M. L. Wolfrom ◽  
S. W. Waisbrot ◽  
Robert L. Brown
Keyword(s):  
Open Chain ◽  
New Synthesis ◽  
Sugar Derivatives

A Synthesis Algorithm for Three-Revolute Manipulators by Using an Algebraic Formulation of Workspace Boundary

1995 ◽  
Vol 117 (2A) ◽  
pp. 298-302 ◽  
Author(s):  
M. Ceccarelli
Keyword(s):  
Multiple Solutions ◽  
Algebraic Form ◽  
Open Chain ◽  
Synthesis Algorithm ◽  
New Synthesis ◽  
Algebraic Formulation ◽  
Workspace Boundary

A new synthesis algorithm for general three-revolute open chain manipulators is proposed making use of an algebraic formulation for the workspace boundary. This algebraic form of a synthesis model is used to formulate design equations and to discuss the number and the type of the multiple solutions.

Superoxide induced cyclizations of metallo-2,2'-bidipyrrins

2003 ◽  
Vol 07 (04) ◽  
pp. 214-219 ◽  
Author(s):  
Martin Bröring ◽  
Christian Hell ◽  
Carsten D. Brandt ◽  
Esther Cónsul Tejero
Keyword(s):  
Room Temperature ◽  
Catalytic Amount ◽  
High Yield ◽  
Sodium Peroxide ◽  
Open Chain ◽  
Potassium Superoxide ◽  
New Synthesis

The reaction of the open-chain tetrapyrrolic ligand 2,2'-bidipyrrin with molecular dioxygen in the presence of a catalytic amount of manganese(II)-acetate was found to produce 10,10'-diformyl-2,2'-bidipyrrin with a remarkable selectivity. To identify the active oxidant in this transformation, 2,2'-bidipyrrin was treated with potassium superoxide, sodium peroxide and manganese(III) acetate, respectively, in dry DMF. While superoxide produces the dialdehyde in high yield, the treatment with peroxide or manganese(III) acetate leads to decomposition only. Nickel(II)-, palladium(II)- and copper(II)-2,2'-bidipyrrin were found to undergo macrocyclization reactions when treated with potassium superoxide in dry DMF at room temperature. While the respective 10-oxocorrolates are formed from the nickel(II)- and palladium(II)-2,2'-bidipyrrins, the copper(II) chelate reacts very slowly and yields copper(III) corrole in low yield. The results strongly point to superoxide as the active oxidant in a recently found new synthesis of corroles.

Stereospecific synthesis of tetrahydrobenzisoquinoline derivatives

1983 ◽  
Vol 36 (1) ◽  
pp. 157 ◽  
Author(s):  
E Gellert ◽  
N Kumar ◽  
D Tober
Keyword(s):  
Optically Active ◽  
Stereospecific Synthesis ◽  
Open Chain ◽  
New Synthesis ◽  
Phenanthroindolizidine Alkaloids

A new synthesis of optically active tetrahydrobenzisoquinolines is described. Cyclization of N-aryl- alkylalanines with retention of configuration was achieved by mild intramolecular Friedel-Crafts acylation. The compounds synthesized this way represent simple analogues of phenanthroindolizidine alkaloids. Some features of the n.m.r. spectra of cyclized and open-chain intermediates are discussed.

scholarly journals Optical activity in ketones. The rotatory dispersion and circular dichroism of m-methyl cyclohexanone and of pulegone in their ketonic absorption bands

1937 ◽  
Vol 163 (915) ◽  
pp. 483-498 ◽  
Keyword(s):  
Optical Activity ◽  
Wave Length ◽  
Small Contribution ◽  
Asymmetric Carbon Atom ◽  
Absorption Bands ◽  
Open Chain ◽  
Aldehydes And Ketones ◽  
Sugar Derivatives ◽  
Absorption Frequencies ◽  
Asymmetric Carbon

Recent investigations of the rotatory dispersions of aldehydes and ketones led to the conclusion that the optical activity of these compounds is due almost entirely to the electrons of the carbonyl group and not directly to the asymmetric carbon atoms. A particularly striking example of this was found in the aldehydic sugar derivative, μ-arabinose pentaacetate, by Hudson, Wolfrom and Lowry (1933), who showed that when the calculated partial rotation contributed by the absorption band between 3000 and 2600 A was subtracted from the observed rotations for the whole molecule, a negligible residual rotation was left at every wave-length at which measurements were made between 6700 and 2300 A. In general, however, absorption frequencies lying in the Schumann region appear to make a small contribution; but the analysis has always been complicated in the cases so far examined by the fact that the molecules contain either two asymmetric carbon atoms, e. g. in camphor (Kuhn and Gore 1931), menthone and carvomenthone (Lowry and Lishmund 1935a), or as many as four in the open-chain sugar derivatives (Hudson and others 1933; Baldwin, Wolfrom and Lowry 1935). The absence of any large direct contribution from the asymmetric atoms might therefore be explained in two ways, namely, either that their partial rotations are actually very small, or, as may well be the case in the sugars (cf. Lowry 1935, p. 274), that, though large, they are of opposing signs and tend to annul one another at wavelengths remote from the region of absorption. It was thus desirable to examine an optically active ketone whose molecule contains only a single asymmetric carbon atom, with no other disturbing factor, and m-methyl cyclohexanone (I) was selected for this purpose.

Tandem Carbon-Radical Peroxidation−Addition to Carbonyl Groups Reaction. A New Synthesis of Steroidal β-Peroxy Lactones

1996 ◽  
Vol 61 (26) ◽  
pp. 9635-9635
Author(s):  
Alicia Boto ◽  
Rosendo Hernández ◽  
Ernesto Suárez ◽  
Carmen Betancor ◽  
María S. Rodríguez
Keyword(s):  
Carbonyl Groups ◽  
New Synthesis

1,3-Selenaphospholes: A New Synthesis from 1,2,3-Selenadiazoles and Kinetically Stabilized Phosphaalkynes1

Synlett ◽  
1991 ◽  
Vol 1991 (04) ◽  
pp. 356-358 ◽  
Author(s):  
Bernd Burkhart ◽  
Steffen Krill ◽  
Yoshinori Okano ◽  
Wataru Ando ◽  
Manfred Regitz
Keyword(s):  
New Synthesis

A New Synthesis and Analysis of Silica Nanowire Periodically Wrapped by Nano-spheres

2016 ◽  
Vol 31 (5) ◽  
pp. 523
Author(s):  
MA Hong-Bing ◽  
BAI Hua ◽  
XUE Chen ◽  
TAO Peng-Fei ◽  
XU Qun-Feng ◽  
...  
Keyword(s):  
New Synthesis
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