Some Observations on the Hydrolysis of the Amides of Primary α-Acetylenic Amines

Some amides of primary α-acetylenic amines were made from the corresponding α-acetylenic alcohols by the Ritter reaction. Depending upon the other substituents on the carbon atom bearing nitrogen and the ethynyl group, hydrolysis resulted in formation of the α-acetylenic amine or in hydration of the triple bond to yield a ketone.

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Comparative studies of the specificities of α-chymotrypsin and subtilisin BPN′. Studies with flexible and ‘locked’ substrates

Biochemical Journal ◽

10.1042/bj1260659 ◽

1972 ◽

Vol 126 (3) ◽

pp. 659-665 ◽

Cited By ~ 9

Author(s):

T. N. Pattabiraman ◽

W. B. Lawson

Keyword(s):

Methyl Ester ◽

Carbon Atom ◽

Binding Site ◽

Comparative Studies ◽

Detrimental Effect ◽

Optically Active ◽

The Other ◽

Optical Isomers ◽

Polar Groups ◽

Hydrolysis Of

Subtilisin BPN′ hydrolysed N-acetyl-l-3-(2-naphthyl)-alanine methyl ester, N-acetyl-l-leucine methyl ester and N-acetyl-l-valine methyl ester, faster than α-chymotrypsin. Of eight ‘locked’ substrates tested, only methyl 5,6-benzindan-2-carboxylate was hydrolysed faster by subtilisin, whereas the other esters were better substrates for chymotrypsin. Compared with the values for chymotrypsin, the stereospecific ratios during the hydrolysis of the optically active locked substrates by subtilisin were decreased by one and two orders of magnitude for bi- and tri-cyclic substrates respectively. The polar groups adjacent to the α-carbon atom of locked substrates did not contribute significantly to the reactivity of the more active optical isomers, but had a detrimental effect on the less active antipodes during hydrolysis by both the enzymes. These studies show that the binding site of subtilisin BPN′ is longer and broader than that of α-chymotrypsin.

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Comments on the paper by A. D. Walsh

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1951.0095 ◽

1951 ◽

Vol 207 (1088) ◽

pp. 30-31 ◽

Cited By ~ 1

Keyword(s):

Carbon Atom ◽

Force Constant ◽

Triple Bond ◽

The Other ◽

Carbon Nucleus ◽

Nucleus Plus ◽

The Difference ◽

Effective Attraction

I agree very much with Dr Walsh that a satisfactory knowledge of effective atomic electronegativities is very important and that we should concentrate on obtaining such knowledge. The effective electronegativity of an atom varies, of course, in different circumstances. This appears to be the explanation of the difference in strength (length and force constant) of the C—H bonds in methane and acetylene. The effective attraction of the carbon atom for the electrons in a C—H bond in methane is a resultant of the attraction of the carbon nucleus plus Is core and the repulsion of the electrons associated with the other three C—H bonds. In acetylene the effective attraction of the carbon atom for the electrons in the C—H bond is the resultant of the attraction of the nucleus plus core and the repulsion of the electrons in the triple bond. Because these last six electrons are drawn away into the triple bond on the far side of the carbon atom from the C—H bond it seems that their repulsion on the electrons in the C—H bond is less than that of the six electrons in the three other C—H bonds in methane which are relatively nearer.

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A FACILE SYNTHESIS AND REACTIONS OF AMINO SELENOLO[2,3-b]PYRIDINE CARBOXYLATE

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v12i1.845 ◽

2015 ◽

Vol 12 (1) ◽

pp. 3910-3918 ◽

Cited By ~ 1

Author(s):

Dr Remon M Zaki ◽

Prof Adel M. Kamal El-Dean ◽

Dr Nermin A Marzouk ◽

Prof Jehan A Micky ◽

Mrs Rasha H Ahmed

Keyword(s):

Biological Activity ◽

Carbonyl Compounds ◽

Mass Spectra ◽

The Other ◽

Pyridine Derivatives ◽

Facile Synthesis ◽

High Biological Activity ◽

Basic Hydrolysis ◽

Pyridine Carboxylate ◽

Hydrolysis Of

Incorporating selenium metal bonded to the pyridine nucleus was achieved by the reaction of selenium metal with 2-chloropyridine carbonitrile 1 in the presence of sodium borohydride as reducing agent. The resulting non isolated selanyl sodium salt was subjected to react with various α-halogenated carbonyl compounds to afford the selenyl pyridine derivatives 3a-f which compounds 3a-d underwent Thorpe-Ziegler cyclization to give 1-amino-2-substitutedselenolo[2,3-b]pyridine compounds 4a-d, while the other compounds 3e,f failed to be cyclized. Basic hydrolysis of amino selenolo[2,3-b]pyridine carboxylate 4a followed by decarboxylation furnished the corresponding amino selenolopyridine compound 6 which was used as a versatile precursor for synthesis of other heterocyclic compound 7-16. All the newly synthesized compounds were established by elemental and spectral analysis (IR, 1H NMR) in addition to mass spectra for some of them hoping these compounds afforded high biological activity.

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Vinylnorbornene in the Ritter reaction

Russian Journal of Applied Chemistry ◽

10.1134/s1070427209060184 ◽

2009 ◽

Vol 82 (6) ◽

pp. 1025-1028

Author(s):

Yu. E. Klimko ◽

S. D. Isaev ◽

D. A. Pisanenko

Keyword(s):

Ritter Reaction ◽

The Ritter Reaction

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THE ALDOBIOURONIC ACIDS OF HEMICELLULOSE B OF OAT HULLS

Canadian Journal of Chemistry ◽

10.1139/v56-049 ◽

1956 ◽

Vol 34 (3) ◽

pp. 338-344 ◽

Cited By ~ 36

Author(s):

E. L. Falconer ◽

G. A. Adams

Keyword(s):

Glucuronic Acid ◽

The Other ◽

Partial Hydrolysis ◽

Oat Hulls ◽

Hydrolysis Of

Partial hydrolysis of hemicellulose B from oat hulls yielded two aldobiouronic acids, which were identified as 2-O-(4-O-methyl-α-D-glucopyruronosyl)-D-xylose and 2-O-(α-D-glucopyruronosyl)-D-xylose respectively. In addition, two aldotriouronic acids were isolated, one yielding on hydrolysis xylose and 4-O-methyl-glucuronic acid, and the other, xylose, galactose, and glucurone.

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Dative behavior of N-heterocyclic carbenes (NHCs) with selenium in Se-NHC compounds

Reviews in Inorganic Chemistry ◽

10.1515/revic-2021-0031 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Munazzah Yaqoob ◽

Mahvish Abbasi ◽

Hira Anwar ◽

Javed Iqbal ◽

Mohammad Asad ◽

...

Keyword(s):

Nitrogen Atom ◽

Carbon Atom ◽

Lone Pair ◽

Heterocyclic Ring ◽

Heterocyclic Carbenes ◽

The Other ◽

Donor Ligands ◽

Important Research ◽

Dative Bond ◽

Back Bonding

Abstract N-heterocyclic carbenes (NHCs) are an eminent class of carbenes having a heterocyclic ring in which a divalent carbon atom is attached directly to a nitrogen atom. In the NHCs, the donation of lone pair is another important research in the dative bonding and not only in NHCs the dative bond plays a functionalized role in the other classes of complex formation like ylidones L → E ← L and carbones L → C ← L. M–NHC bond is L-M sigma-dative bond and NHCs are considered as strong sigma-donor ligands. The clear picture of the M–NHC bond can be better understood by M–NHC pi-interaction. M-L pi interaction is comprised of two steps. One is L → M sigma-donation and M → L π* back bonding. This dative donor nature of NHC and also its behavior in organoselenium is studied through DFT in which it’s optimized structure, bond lengths, molecular vibrations are calculated.

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