Studies on antiallergic agents. I. Phenyl-substituted heterocycles with a 5-tetrazolyl or N-(5-tetrazolyl)carbamoyl group.

New derivatives of 6-phenylcomanic acid

“…The starting ethyl 5,6 dibromo 2,4 dioxo 6 phenylhexanoate is available compound and can be easily obtained by condensation of benzylideneacetone and diethyl oxalate with subsequent bromination of the thus forming ethyl (E) 2,4 dioxo 6 phenylhex 5 enoate. 2 The reaction of ethyl 6 phenyl comanoate 1 with ammonia even under drastic enough conditions (heating in ethanol at 60°C for 24 h in a sealed tube) does not affect the pyrone ring and stops at the stage of 4 oxo 6 phenyl 4H pyran 2 carboxamide 3 (79%), 7 whereas the recyclization to 4 hydroxy 6 phenylpyridine 2 carboxamide 4 (83%) was successful only on heating ester 1 or amide 3 with ammonia in DMSO at 110°C for 12 h in a sealed tube. Hydrazine hydrate and hydroxyl amine react with ester 1 at ∼20°C for 0.5-1 h only at the ester group, giving the earlier undescribed hydrazide 5 (90%) and hydroxamic acid 6 (48%).…”

Studies on a New Antiallergic Pyridinecarboxamide TA-5707F and Its Sodium Salt (TA-5707) I. Inhibition of IGE-lnduced Passive Cutaneous Anaphylaxis (PCA) in Rats

“…Thus, great efforts have been made to develop orally active antiallergics. We have investigated the effect of sub stitution of other heterocycles for the chromone structure of DSCG on the anti allergic activity using PCA in rats as the test system and arrived at a new series of orally effective anti allergics-N-tetrazolyl pyri d1necarboxamides (1)(2)(3). Out of these, we have selected 6-methyl-N-(1 H-tetrazol-5 yl)-2-pyridinecarboxamide (TA-5707F, Fig.…”

“…Rat PCA: Rat PCA was induced as described elsewhere (1) except that the rats were challenged with antigen 48 hr after the sensitization. In most experiments, 15-fold diluted antisera were used for passive sensitization.…”

Route to Chiral Tetrahydrofuran Acetals via Pd-Catalyzed Asymmetric Allylic Cycloaddition of Vinyl Epoxides with β-Keto Enol Ethers

“…Recent research efforts including our group have demonstrated that Pd-catalyzed asymmetric allylic cycloaddition of vinyl epoxides or vinylethylene carbonates with electron-deficient alkenes is able to generate multisubstituted chiral THFs in high efficiency. We therefore envisioned that the allylic cycloaddition of vinyl epoxides with β-keto enol ethers could produce more functionalized THF acetals. Concretely, we anticipated that the intermolecular addition of the zwitterionic allylpalladium intermediate I , which was generated from the reaction of vinyl epoxide 1 with a palladium catalyst, to the β-keto enol ethers 2 could afford intermediate II possessing an acetal subunit and an enolate anion (Figure C).…”