THE OXIDATION OF 3-(N-BENZYLACETAMIDO)-1,2-PROPANEDIOL TO N-BENZYLACETAMIDOACETALDEHYDE AND RING CLOSURE OF THE LATTER TO ISOQUINOLINEL

1955 ◽  
Vol 33 (2) ◽  
pp. 365-374 ◽  
Author(s):  
Arlen W. Frank ◽  
C. B. Purves
Keyword(s):  
Acetyl Derivative ◽  
Oxidative Cyclization ◽  
Lead Tetraacetate ◽  
Ring Closure ◽  
Diethyl Acetal ◽  
Sodium Metaperiodate

Fischer's synthesis of isoquinoline by the oxidative cyclization of benzylaminoacetaldehyde diethyl acetal with 20% oleum was found to give a yield of 8.5%, but his isolation of the intermediate aldehyde could not be repeated. The N-acetyl derivative, N-benzylacetamidoacetaldehyde, however, was synthesized as a somewhat unstable oil, b.p. 129–131° (0.12 mm.), and was cyclized in 7.5% yield to isoquinoline. This synthesis involved the hydrogenation of 3-benzylideneamino-1,2-propanediol to 3-benzylamino-1,2-propanediol, b.p. 152-155° (0.5 mm.); hydrochloride, m.p. 92–94.5°. The N-acetyl derivative, 3-(N-benzylacetamido)-1,2-propanediol, b.p. 188° (0.12 mm.), was then oxidized with sodium metaperiodate; the behavior of other intermediates in the synthesis toward periodate, and also lead tetraacetate, was studied. The following additional compounds were thought to be new: 3-veratrylideneamino-1,2-propanediol, m.p. 123–125°; 3-veratrylamino-1,2-propanediol, b.p. 207–214° (0.4 mm.); the hydrochloride, m.p. 151–152°; 3-(N-benzylacetamido)-1,2-diacetoxypropane, b.p. 196–199° (0.7 mm.), and N-benzylacetamidoacetaldehyde 2,4-dinitrophenylhydrazone, m.p. 315–316°.

Sequential Gold-Catalyzed Carbene Transfer/Ring Closure: Oxidative Cyclization of β-(2-Alkynylphenyl)-α,β-ynones to Indenofuranones

2018 ◽  
Vol 360 (24) ◽  
pp. 4790-4794 ◽  
Author(s):  
Navnath Rode ◽  
Fabio Marinelli ◽  
Antonio Arcadi ◽  
Tapas Adak ◽  
Matthias Rudolph ◽  
...  
Keyword(s):  
Oxidative Cyclization ◽  
Ring Closure ◽  
Carbene Transfer

Oxidative cyclization of carbonyl derivatives. 5-Imino-Δ1-1,2,4-triazolines from alkylideneimino guanidines

1978 ◽  
Vol 56 (16) ◽  
pp. 2194-2196 ◽  
Author(s):  
Lubomira M. Cabelkova-Taguchi ◽  
John Warkentin
Keyword(s):  
Sodium Carbonate ◽  
Oxidation Product ◽  
Methylene Chloride ◽  
Oxidative Cyclization ◽  
Lead Tetraacetate ◽  
Carbonyl Derivatives ◽  
A Minor ◽  
Major Oxidation

Treatment of 2-propylideneimino guanidinium acetate with lead tetraacetate, in methylene chloride containing solid sodium carbonate, afforded the previously unknown 3,3-dimethyl-5-imino-Δ1-1,2,4-triazoline. Similarly, N,N′-diphenyl-N″-(2-propylideneimino)guanidinium acetate afforded Z-4-phenyl-5-phenylimino-Δ1-1,2,4-triazoline as the major oxidation product and the corresponding E isomer as a minor product. Stereochemistry was established spectrophotometrically and also by isomerizing the minor (E) isomer to the major (Z) isomer.

Oxidative cyclization of 1-octadecanol and hydroxy fatty esters with lead tetraacetate

1984 ◽  
Vol 61 (6) ◽  
pp. 1024-1027 ◽  
Author(s):  
M. Hashmi ◽  
M. Khan ◽  
M. S. Ahmad ◽  
F. Ahmad ◽  
S. M. Osman
Keyword(s):  
Oxidative Cyclization ◽  
Lead Tetraacetate ◽  
Fatty Esters

ChemInform Abstract: OXIDATIVE CYCLIZATION OF UNSATURATED FATTY ACIDS WITH LEAD TETRAACETATE

1983 ◽  
Vol 14 (51) ◽  
Author(s):  
M. HASHMI ◽  
M. KHAN ◽  
M. S. JUN. AHMAD ◽  
F. AHMAD ◽  
S. M. OSMAN ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Oxidative Cyclization ◽  
Lead Tetraacetate

Aril Azines. II. Hydrogenation of p-Tolil Monoazine

1975 ◽  
Vol 53 (5) ◽  
pp. 748-752 ◽  
Author(s):  
Peter Yates ◽  
E. M. Levi
Keyword(s):  
Hydrogen Atom ◽  
Carbon Atom ◽  
Sodium Borohydride ◽  
Sodium Methoxide ◽  
Major Product ◽  
Lead Tetraacetate ◽  
Ring Closure ◽  
Carbonyl Carbon Atom ◽  
Carbonyl Carbon ◽  
Independent Synthesis

Hydrogenation of p-tolil monoazine (1b) over palladium-on-charcoal gives as the major product 4,5-dihydro-5-(p-toluyl)-3,4,5-tri-(p-tolyl)-1H-pyrazol-4-ol (2b), which has previously been obtained by treatment of 1b with sodium methoxide. Several minor products are formed, which include p-tolualdehyde, p-toluic acid, and p-toluamide, p-tolunitrile, p-tolualazine, and 3,4,5-tri-(p-tolyl)-4H-pyrazo-4-ol (9). The structure of the last compound, which is also formed on reduction of 1b with sodium borohydride, was established by its independent synthesis from 1,2,3-tri-(p-tolyl)-1,3-propanedione by oxidation with lead tetraacetate followed by treatment with hydrazine. It is suggested that 2b arises via reduction of a C=N bond of 1b and aldol ring closure. The minor hydrogenation products are of interest in that their formation involves C—C hydrogenolysis; it is suggested that this is initiated by addition of a hydrogen atom to a carbonyl carbon atom of 1b.

Carbocyclic Construction: The Deng Synthesis of (-)-Plicatic Acid

2013 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Brefeldin A ◽  
Conjugate Addition ◽  
Oxidative Cyclization ◽  
Ring Closure ◽  
Silyl Ether ◽  
University Of Pittsburgh ◽  
University Of Wisconsin ◽  
Institute Of Technology ◽  
The University ◽  
Academy Of Sciences

Tehshik P. Yoon of the University of Wisconsin uncovered (J. Am. Chem. Soc. 2009, 131, 14604) conditions for the crossed photodimerization of acyclic enones. Minoru Isobe of Nagoya University extended (Synlett 2009, 1157) conjugate addition–intramolecular epoxide opening to substrates such as 4, leading to the cyclobutane 6 with high diastereocontrol. In the course of a total synthesis of (+)-brefeldin A, Jinsung Tae of Yonsei University established (Synlett 2009, 1303) conditions for the trans-selective cyclization of 7 to 8. Cyclization with TiCl4 gave the alternative cis diastereomer. Several methods have been put forward for the conversion of carbohydrate derivatives to carbocycles. Yeun-Mi Tsai of the National Taiwan University found (Tetrahedron Lett . 2009, 50, 3805) that acyl silanes such as 9 cyclized efficiently under free radical conditions, leading to the silyl ether 10. Tanmaya Pathak of the Indian Institute of Technology, Kharagpur, developed (Eur. J. Org. Chem. 2009, 872) the tandem conjugate addition– intramolecular alkylation conversion of 11 to 13. Slawomir Jarosz of the Polish Academy of Sciences, Warsawza, observed (Heterocycles 2009, 80, 1303) that the oxime derived from 14 cyclized to 15. The cyclization was accelerated by high pressure. Cyclohexanes can also be prepared from carbohydrates. Tony K. M. Shing of the Chinese University of Hong Kong showed (Organic. Lett. 2009, 11, 5070) that the nitrile oxide derived from 16 cyclized to 17, that he carried on to (-)-gabosine O. John K. Gallos of the Aristotle University of Thessaloniki described (Tetrahedron Lett. 2009, 50, 6916) related work. Paul E. Floreancig of the University of Pittsburgh devised (Organic. Lett. 2009, 11, 3152) conditions for the oxidative cyclization of 18 to 19. Ring closure proceeded with high equatorial selectivity. Kou Hiroya of Tohoku University found (J. Org. Chem. 2009, 74, 6623) that the single oxygenated stereogenic center of 20 directed the dissolving metal reduction–enolate trapping, leading to 21. Similarly, Susumu Kobayashi of the Tokyo University of Science showed (Synlett 2009, 1605) that the oxygenated stereogenic centers of 22 set the alkylated centers of 23. Many marine organisms are able to carry out brominative and chlorinative polyolefin cyclizations.

scholarly journals Oxidative cyclization of N-methyl-dopa by a fungal flavoenzyme of the amine oxidase family

2018 ◽  
Vol 293 (44) ◽  
pp. 17021-17032
Author(s):  
Majd Lahham ◽  
Tea Pavkov-Keller ◽  
Michael Fuchs ◽  
Johannes Niederhauser ◽  
Gabriel Chalhoub ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Amine Oxidase ◽  
Oxidative Cyclization ◽  
Ring Closure ◽  
Hydroxyl Group ◽  
Binding Modes ◽  
Recombinant Production ◽  
Methyl Dopa ◽  
Berberine Bridge Enzyme ◽  
Ring Structures

Flavin-dependent enzymes catalyze many oxidations, including formation of ring structures in natural products. The gene cluster for biosynthesis of fumisoquins, secondary metabolites structurally related to isoquinolines, in the filamentous fungus Aspergillus fumigatus harbors a gene that encodes a flavoprotein of the amine oxidase family, termed fsqB (fumisoquin biosynthesis gene B). This enzyme catalyzes an oxidative ring closure reaction that leads to the formation of isoquinoline products. This reaction is reminiscent of the oxidative cyclization reported for berberine bridge enzyme and tetrahydrocannabinol synthase. Despite these similarities, amine oxidases and berberine bridge enzyme–like enzymes possess distinct structural properties, prompting us to investigate the structure–function relationships of FsqB. Here, we report the recombinant production and purification of FsqB, elucidation of its crystal structure, and kinetic analysis employing five putative substrates. The crystal structure at 2.6 Å resolution revealed that FsqB is a member of the amine oxidase family with a covalently bound FAD cofactor. N-methyl-dopa was the best substrate for FsqB and was completely converted to the cyclic isoquinoline product. The absence of the meta-hydroxyl group, as e.g. in l-N-methyl-tyrosine, resulted in a 25-fold lower rate of reduction and the formation of the demethylated product l-tyrosine, instead of a cyclic product. Surprisingly, FsqB did not accept the d-stereoisomer of N-methyltyrosine, in contrast to N-methyl-dopa, for which both stereoisomers were oxidized with similar rates. On the basis of the crystal structure and docking calculations, we postulate a substrate-dependent population of distinct binding modes that rationalizes stereospecific oxidation in the FsqB active site.

Synthesis of Some 1H-1,2,4-Triazole, 4H-1,2,4-Triazole, Thiazolo[2,3-c]-1,2,4-triazole and 5H-1,2,4-Triazolo-[3,4-b][1,3]thiazine Derivatives by Metal Compound-Mediated Oxidative Cyclization of Derivatives of 2-(Phenylmethylidene)hydrazinecarboximidothioic Acid

1997 ◽  
Vol 50 (9) ◽  
pp. 911 ◽  
Author(s):  
Abdelselam S. Ali ◽  
John S. Wilkie ◽  
Kevin N. Winzenberg
Keyword(s):  
Oxidative Cyclization ◽  
Lead Tetraacetate ◽  
Metal Compound ◽  
Cyclization Reactions ◽  
Triazole Derivatives ◽  
Derivatives Of

Reaction of the methyl 2-(phenylmethylidene)hydrazinecarboximidothioate derivatives (3a–d) and (6a,b) with iron(III) chloride afforded the 5-methylsulfanyl-3-phenyl-4H-1,2,4-triazole derivatives (4a–d) and the 5-methylsulfanyl-3-phenyl-1H-1,2,4-triazole derivatives (7a,b). This reaction was extended to the synthesis of the 3-phenyl-5,6-dihydrothiazolo[2,3-c]-1,2,4-triazole derivatives (10a,b) and the 3-phenyl-6,7-dihydro-5H-1,2,4-triazolo[3,4-b][1,3]thiazine derivatives (10c,d). Reaction of 5-(3-chlorophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (12a) with 1,2-dibromoethane gave (10a) together with the isomeric 2-(3-chlorophenyl)-5,6-dihydrothiazolo[3,2-b][1,2,4]triazole (13a); similarly, reaction of (12a) with 1,3-dibromopropane afforded (10c) along with 2-(3-chlorophenyl)-6,7-dihydro-5H-[1,2,4]triazolo[5,1-b][1,3]thiazine (13b). The use of nickel peroxide and lead tetraacetate in place of iron(III) chloride was investigated for some of these oxidative cyclization reactions.

Oxidative cyclization of unsaturated fatty acids with lead tetraacetate

1983 ◽  
Vol 60 (8) ◽  
pp. 1538-1543 ◽  
Author(s):  
M. Hashmi ◽  
M. Khan ◽  
M. S. Ahmad ◽  
F. Ahmad ◽  
S. M. Osman
Keyword(s):  
Fatty Acids ◽  
Unsaturated Fatty Acids ◽  
Oxidative Cyclization ◽  
Lead Tetraacetate
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