The synthesized potassium 2-benzoylhydrazinecarbodithioate was cyclized
to yield 4-amino-5-phenyl-4H-l,2,4-triazole-3-thiol (3) compound, and this was further cyclized
with p-amino benzoic acid in polyphosphoric acid to obtain the fused 4-(3-phenyl[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-yl)aniline (4).
The hydrazide is cyclized
by the reaction with CS2 in the presence of KOH in ethanol under reflux to give oxadiazole derivative 4 which is followed by reaction with ethyl chloroacetate and then with hydrazine hydrate to afford oxadiazole ester derivative 5 and then oxadiazole hydrazide derivative 6, respectively.
In an acid medium, CBD is cyclized
(it forms a new carbon ring) to become THC.
A lysine residue was then added to the C-terminus of the cyclized
peptide, generating the cyclic peptide iCREKA.
The latter is further oxidized and cyclized
into cis-(+)-12-oxophytodienoic acid (cis-(+)-OPDA) by the actions of allene oxide synthase (AOS) and allene oxide cyclase (AOC) .
Accordingly, the arylideneamino derivatives 4a-c were successfully cyclized
to their 1,2,4-triazolo[3,4-b][1,3,4] thiadiazole analogues 5a-c by the action of iodine in acetonitrile.
These intracellular steps occur in the cytosol and ER and use acetyl CoA to make a 30-carbon linear molecule, squalene, which is further cyclized
and modified into the 27-carbon cholesterol [101, 102] (Figure 2).
The acetylacetone (acac) method is based on the Hantzsch synthesis, where 2,4-pentanedione (acac), ammonium acetate, and formaldehyde are cyclized
to form dihydropyridine 3,5-diacetyl-1,4-dihydrolutidine (DDL).
In first step synthesis of N-phenylanthranilic acid 3 was carried out by Ullmann coupling of anthranilic acid and bromo benzoic acid which cyclized
in the presence of sulfuric acid to form 9-oxo-9,10-dihydro-4-acridinecarboxylic acid 4.
Cyclotides are family of backbone cyclized
, cysteine rich peptides (~30 amino acid residues) produced by Rubiaceae and Violaceae plant families (Craik et al.
What we observed was an almost quantitative formation of sugar oxazoline derivative, the intra-molecularly cyclized
product of [beta]-N-acetylgluosaminyl fluoride, as the result of neighboring participation of the acetamido group.
If the tetrapeptide imide structure cyclized
from head to tail, the resulting product would have two five-membered cyclic imides and a twelve-membered cyclic peptide.