Efficient preparation of some new 1-carbamato-alkyl-2-naphthols using N-halo reagents in neutral media

Tandem cyclocondensation-Knoevenagel–Michael reaction of phenyl hydrazine, acetoacetate derivatives and arylaldehydes

“…Since DCDBTSD contains bromine atoms which are bonded to nitrogen atoms in the heterocyclic ring, by in situ generation of Br + from the catalyst, the reaction is catalyzed. So, in a proposed reaction mechanism which is supported by the literature, 25,[32][33][34] we suggest that b-ketoester and the catalyst produce intermediates I and II (Scheme 3). Then, phenyl hydrazine attacks I and II and intermediate III is obtained by the removal of one molecule of alcohol and is then converted to IV after tautomerization.…”

“…Some specific features of N-halo reagents including the high activity of the N-X bond and the various modes of splitting of this bond have led to their wide application in organic synthesis. 22 Based on the above facts and in continuation of our previous studies on the application of N-halo reagents in organic synthesis, [23][24][25][26][27][28][29][30][31] we have recently introduced a new N-halo reagent, namely N,2-dibromo-6-chloro-3,4-dihydro-2Hbenzo[e][1,2,4]thiadiazine-7-sulfonamide 1,1-dioxide (DCDBTSD), as an efficient and novel catalyst (Scheme 1 and Fig. 1).…”

Composite Hydrogels Using Bioinspired Approach with in Situ Fast Gelation and Self-Healing Ability as Future Injectable Biomaterial

“…The 1 H NMR spectra ( Figure S2) of pure PEG showing the characteristic peaks (a, 5, 6) of PEG backbone at 3.6 ppm, 33 while after end group modification with 4-formyl benzoic acid indicate additional peaks at 7.9 ppm, at 8.2 ppm and at 10.10 ppm, assigned to the aromatic carbon (2, 3) and aldehyde groups (1), respectively of the benzaldehyde end functionality. 34 Similarly, in case of chitosan, some new peaks appeared after grafting reaction, at 2.4 ppm and at 4.1 ppm, which characterize the methylene (β, γ) and (α) protons, respectively, of Lglutamic acid. 35,36 Therefore, the 1 The FTIR spectra of PEG ( Figure S3A) after end-group functionalization with 4-formyl benzoic acid showing an additional peak at 1707 cm -1 , which is the characteristic band of aldehyde (C=O) groups, while the intensity at 2817 cm -1 becomes more intense, due to the incorporation of the aromatic ring (-C-H stretching).…”

Design and characterization of nano-silica-bonded 3-n-propyl-1-sulfonic acid imidazolium chloride {nano-SB-[PSIM]Cl} as a novel, heterogeneous and reusable catalyst for the condensation of arylaldehydes with β-naphthol and alkyl carbamates

“…For example, a-aminoalkyl-b-naphthol derivatives have bradycardiac and hypotensive properties [34,35]. One of the rational synthetic approaches toward a-carbamatoalkyl-b-naphthols is the catalyzed condensation of arylaldehydes with b-naphthol and alkyl carbamates [36][37][38][39][40][41][42][43][44][45][46][47][48][49][50].…”