scholarly journals ‘Atypical Ugi’ tetrazoles

2020 ◽  
Vol 56 (12) ◽  
pp. 1799-1802
Author(s):  
Eman M. M. Abdelraheem ◽  
Imogen Goodwin ◽  
Shabnam Shaabani ◽  
Michel P. de Haan ◽  
Katarzyna Kurpiewska ◽  
...  
Keyword(s):  
Isomeric Product

We surprisingly found that combining the substrates of Ugi tetrazole reaction gives two different constitutional isomeric Ugi products A and B. A is the expected classical Ugi products whereas B is an isomeric product (‘atypical Ugi’).

Chemical Reactions of Rubber

1943 ◽  
Vol 16 (1) ◽  
pp. 111-123
Author(s):  
R. L. Sibley
Keyword(s):  
Molecular Weight ◽  
Atmospheric Pressure ◽  
Rapid Heating ◽  
Slow Heating ◽  
Gutta Percha ◽  
Volatile Products ◽  
Almost All ◽  
Isomeric Product ◽  
Derivatives Of ◽  
Complete Investigation

Abstract Most of the literature descriptive of the various known derivatives of rubber is found published as patents rather than as technical papers, thus indicating the commercial possibilities that may be expected from these developments. Fisher, Schidrowitz and, more recently, Jones have summarized and discussed the chemistry of rubber and its commercial derivatives. The decomposition of rubber by heat has been studied by several investigators. Williams showed that isoprene is one of the main products formed by the destructive distillation of either caoutchouc or gutta percha. Later investigators have shown that slow heating in vacuo at 300° C converts somewhat more than one-half of rubber hydrocarbon into a solid, thermoplastic, isomeric product, which has a high molecular weight and less unsaturation than that of the original hydrocarbon. Rapid heating, especially in vacuo, converts almost all the rubber into volatile products. The most complete investigation of the products obtained by the heat decomposition of rubber apparently was carried out by Midgley and Henne. These investigators destructively distilled 200 pounds of pale crepe rubber in 16-pound batches by raising the temperature as rapidly as possible to 700° C at atmospheric pressure in an iron kettle. The condensate was fractionally distilled, and cuts were made every degree between 50 to 176° C. Each cut was then separately examined. Twenty-three different hydrocarbons were identified in the distillate.

scholarly journals Pyridoxal-5′-phosphate as an oxygenase cofactor: Discovery of a carboxamide-forming, α-amino acid monooxygenase-decarboxylase

2018 ◽  
Vol 115 (5) ◽  
pp. 974-979 ◽  
Author(s):  
Ying Huang ◽  
Xiaodong Liu ◽  
Zheng Cui ◽  
Daniel Wiegmann ◽  
Giuliana Niro ◽  
...  
Keyword(s):  
Amino Acid ◽  
Flavin Adenine Dinucleotide ◽  
Sequence Similarity ◽  
In Vitro Assays ◽  
Complete Conversion ◽  
Mechanistic Studies ◽  
Biochemical Characteristics ◽  
Biochemical Studies ◽  
Isomeric Product

Capuramycins are antimycobacterial antibiotics that consist of a modified nucleoside named uridine-5′-carboxamide (CarU). Previous biochemical studies have revealed that CarU is derived from UMP, which is first converted to uridine-5′-aldehyde in a reaction catalyzed by the dioxygenase CapA and subsequently to 5′-C-glycyluridine (GlyU), an unusual β–hydroxy-α-amino acid, in a reaction catalyzed by the pyridoxal-5′-phosphate (PLP)-dependent transaldolase CapH. The remaining steps that are necessary to furnish CarU include decarboxylation, O atom insertion, and oxidation. We demonstrate that Cap15, which has sequence similarity to proteins annotated as bacterial, PLP-dependent l-seryl-tRNA(Sec) selenium transferases, is the sole catalyst responsible for complete conversion of GlyU to CarU. Using a complementary panel of in vitro assays, Cap15 is shown to be dependent upon substrates O2 and (5′S,6′R)-GlyU, the latter of which was unexpected given that (5′S,6′S)-GlyU is the isomeric product of the transaldolase CapH. The two products of Cap15 are identified as the carboxamide-containing CarU and CO2. While known enzymes that catalyze this type of chemistry, namely α-amino acid 2-monooxygenase, utilize flavin adenine dinucleotide as the redox cofactor, Cap15 remarkably requires only PLP. Furthermore, Cap15 does not produce hydrogen peroxide and is shown to directly incorporate a single O atom from O2 into the product CarU and thus is an authentic PLP-dependent monooxygenase. In addition to these unusual discoveries, Cap15 activity is revealed to be dependent upon the inclusion of phosphate. The biochemical characteristics along with initiatory mechanistic studies of Cap15 are reported, which has allowed us to assign Cap15 as a PLP-dependent (5′S,6′R)-GlyU:O2 monooxygenase-decarboxylase.

Isomeric Product Distributions from the Self-Reaction of Propargyl Radicals

2005 ◽  
Vol 109 (27) ◽  
pp. 6056-6065 ◽  
Author(s):  
Weiyong Tang ◽  
Robert S. Tranter ◽  
Kenneth Brezinsky
Keyword(s):  
The Self ◽  
Product Distributions ◽  
Propargyl Radicals ◽  
Isomeric Product

Synthetic approaches towards 5H-[1]benzopyrano[3,4-c]pyridin-5-ones

2005 ◽  
Vol 2005 (1) ◽  
pp. 38-40 ◽  
Author(s):  
Adel S. Girgis ◽  
Hanaa M. Hosni ◽  
Atef Kalmouch
Keyword(s):  
Single Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthetic Approaches ◽  
Isomeric Product

The construction of 5H-[1]benzopyrano[3,4-c]pyridin-5-ones 2 was achieved through the reaction of 1-aryl-3-(2-hydroxyphenyl)-2-propen-1-ones 1 with malononitrile in alcoholic KOH solution affording the compound 2 along with 2-alkoxy-4-amino-6-aryl-3,5-pyridinedicarbonitriles 3. Single crystal X-ray diffraction of 3e confirmed the established structure and excluded the formation of the isomeric product 4.

scholarly journals Study of methylation reactions of 2-phenylquinazoline-4-tion with “soft” and “hard” methylation agents and determination of its biological activity

2021 ◽  
Vol 258 ◽  
pp. 04023
Author(s):  
B Sapaev ◽  
F.E Saitkulov ◽  
A.A Tashniyazov ◽  
OU Normurodov
Keyword(s):  
Biological Activity ◽  
Reaction Time ◽  
Methyl Iodide ◽  
Dimethyl Sulfate ◽  
Reaction Centers ◽  
Reaction Proceeds ◽  
Alkylation Reactions ◽  
Isomeric Product

Alkylation reactions of 2-phenylquinazoline-4-thion with methylation agents “soft” (methyl iodide) and “hard” (dimethyl sulfate, methyltozylate) were studied. It was found that the reaction proceeds with the formation of alkyl products at the N3 - and S4 - reaction centers, depending on the methylation agent, solvent and temperature. This indicated the ambivalent nature of the 2-phenylquinazoline-4-tion anion. Prolongation of the reaction time leaded to the formation of a second isomeric product (VII). A slight increase in phenyl N3-product (VII) yield was noted when dimethyl sulfate and methylfolate were used as methylation agents. In non-polar proton-free solvent DMF and dipolar proton-free solvent acetonitrile, only N-methyl product (VII) was formed because of the reaction. An increase in the polarity of the solvent and the “hardness” of the methylation agent leads to an increase in the yield of N3 products.

Competing isomeric product channels in the 193 nm photodissociation of 2-chloropropene and in the unimolecular dissociation of the 2-propenyl radical

2001 ◽  
Vol 114 (10) ◽  
pp. 4505 ◽  
Author(s):  
Julie A. Mueller ◽  
Bradley F. Parsons ◽  
Laurie J. Butler ◽  
Fei Qi ◽  
Osman Sorkhabi ◽  
...  
Keyword(s):  
Unimolecular Dissociation ◽  
193 Nm ◽  
Isomeric Product

Synthesis and crystal structure of the fourth isomeric product of the reaction of norbornadiene with sulfur and dodecacarbonyltriiron

1991 ◽  
Vol 401 (1-2) ◽  
pp. 65-73 ◽  
Author(s):  
A.I. Nekhaev ◽  
S.D. Alekseeva ◽  
B.I. Kolobkov ◽  
G.G. Aleksandrov ◽  
M.T. Toshev ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Synthesis And Crystal Structure ◽  
Isomeric Product

scholarly journals Isomeric Product Detection in the Heterogeneous Reaction of Hydroxyl Radicals with Aerosol Composed of Branched and Linear Unsaturated Organic Molecules

2014 ◽  
Vol 118 (49) ◽  
pp. 11555-11571 ◽  
Author(s):  
Theodora Nah ◽  
Haofei Zhang ◽  
David R. Worton ◽  
Christopher R. Ruehl ◽  
Benjamin B. Kirk ◽  
...  
Keyword(s):  
Hydroxyl Radicals ◽  
Organic Molecules ◽  
Heterogeneous Reaction ◽  
Isomeric Product
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