The hitherto unknown 2‐isopropyl‐6,8‐dibromo‐4H‐3,1‐benzoxazin‐4‐one (2) was subjected to condensation with either primary or secondary amines affording the benzamide derivatives (3—7), while with alcohols in presence of the base, corresponding esters were obtained (8 and 9). Acylation of the hydrazide (12) or its cyclized form (13) gave (14—17). The quinazolinone derivative (18) was obtained either when (12) was reacted with nitrous acid or via fusion of (2) with ammonium acetate. The thione (20) which was obtained via reaction of (18) with Lawesson's reagent, was subjected to either alkylation yielding (21—25) or desulphurization with primary amines affording (26 and 27). Treatment of (18) as well as (20) with a chlorinating agent provided (29, 30) and (28, 29) mixtures, respectively. Ten of our compounds were examined against Sclerotium cepivorum as well as Botrytis allii on PDA media. These compounds showed a significant reduction of mycelial growth and scleratia number of these fungi which cause the white rot and neck rot diseases of onion.

7-Amino-1,2,3,4-tetrahydro-4-oxo-2-thioxo-5-(3,4,5-trimethoxyphenyl)pyrido[2,3-d]pyrimidine (1) was prepared and reacted with methyl iodide and ethyl chloroacetate to give the S-alkylated products 2 and 3, respectively. The reaction of 1 or 3 with hydrazine hydrate yielded the same 2-hydrazino derivative 4. Treatment of 4 with 2,4-pentanedione, 2-acetylcyclohexanone and ethyl acetoacetate afforded the corresponding pyrazolylpyrido[2,3-d]pyrimidine derivatives (5-7), while phthalic anhydride gave the phthalazinyl compound 8. Ethoxymethylenemalononitrile with the hydrazine 4 formed the fused 1,2,4-triazepine 9, while triazolopyrido[2,3-d]pyrimidines were obtained from the reaction of 4 with benzylidene malononitrile or benzaldehyde (forming 10), acetic acid/anhydride (giving 11), and ethyl chloroformate (giving 12). Scheme 4 Reagents: a, Ac 2 O in AcOH, D; b, Ar'CH=C(CN) 2 or Ar'CHO; c, ClCO 2 Et; d, EtOCH=C(CN) 2 (b-d ):all in pyridine, D

A series of novel oxapyridazinone derivatives has been synthesized via cyclization of the corresponding sodium salt of α‐sulfonated fatty acid hydrazide with chloroacetic acid in the presence of sodium acetate and acetic anhydride. The structures of the prepared compounds were elucidated using different spectroscopic and elemental analysis. The surface properties (surface tension, CMC value and area per molecule), the thermodynamic stability and antimicrobial activities of the prepared compounds were determined and compared to standard trade material Texapone® N‐70. The prepared compounds exhibit surface activity comparable to the standard and thus can be used as anionic surfactants.

No abstract

1‐(6‐Phenyl) and 1‐(6‐(4‐tolyl)‐3‐oxidopyridinium betaines (1a, b) react as 1,3‐dipoles with conjugated olefines, namely 4‐vinylpyridine, ethyl cinnamate and styrene as 2π‐1,3‐dipolarophiles to give 2,6‐cycloadducts [6‐substituted‐8‐azabicyclo[3,2,1]oct‐3‐en‐2‐ones (3a, b, 4a, b and 5b)] and with butadiene and furan as 4π‐dipolarophiles to give 2,4‐cycloadducts [7‐substituted‐7‐azabicyclo[4,3,1]deca‐3,8‐diene‐10‐one] and 3‐6‐phenylpyridazin‐3‐yl)‐3‐aza‐10‐oxatricyclo‐[5,2,1,12,6]undeca‐4,8‐diene‐11‐one (9a). Structural and configurational assignments were based on H.n.m.r. spectral analysis.

4H,5H‐6‐Phenyl (1a) and 6‐p‐phenoxyphenyl (1b) pyridazin‐3(2H)‐ones were reacted with aromatic aldehydes to give 4‐arylmethylpyridazm‐3(2H)‐ones (2a‐g), Oxidation of (2a‐g) with various oxidising agents (selenium dioxide in ethanol or chromium trioxide in acetic acid) gave 4‐aroyl‐6‐arylpyridazin‐3(2H)‐ones (3a‐g). Chlorination of (3a‐g) with phosphorous oxychloride afforded 4‐aroyl‐6‐aryl‐3‐chloropyridazine (4a‐g). 1H‐3‐Aryl‐5‐phenylpyrazolo[3,4‐c]pyridazines (5a‐d) were obtained by heating (4a‐d) with excess hydrazine hydrate. Hydroxyamination of (3e‐g) with iydroxylamine gave aryl‐4(6‐p‐phenoxyphenyl‐2,3‐dihydro‐3‐oxo)pyridazinyl oxime (6a‐c). Silylation of oximes (6b & 6c) gave (7a & 7b) as acyclic compound instead of the expected seven ‐ membered ‐ ring compound (8).

The benzoxazinone derivative 2‐(6,8‐dibromo‐4‐oxo‐4H‐benzo[d]‐1,3‐oxazin‐2‐yl)‐3‐(4‐methoxyphenyl) acrylonitrile (1) has been used as a starting material for preparation of the hitherto unknown pyrazoloquinazolinone and quinazolinone derivatives. Under different conditions the benzoxazinone (1) was reacted with hydrazine hydrate to provide the pyrazolocarbonitrile derivative (2) and the azine derivative (3) and/or the pyrazoloquinazoline derivative (4). When (4) was conducted to react either with EAA (ethyl acetoacetate) or Ac2O/AcOH (acetic anhydride/acetic acid) mixture or phthalic anhydride/acetic acid mixture, the pyrazoloquinazoline carbonitrile (5), pyrazolo‐quinazoline acetic acid (6) or the pyrazoloquinazolinone derivative (7) were formed respectively. When (1) was reacted with phenylhydrazine, a mixture of the quinazolinone derivative (8) and the hydrazone derivative (9) were obtained. The benzoxazinone derivative (1) was found also to react with benzylamine in ethanol or without solvent to give the quinazolinone derivative (10) or the quinazolindione (11) respectively. Fusion of (1) with ammonium acetate yielded the quinazolinone (12), which was methylated to give (13) and thiated to the thioxyquinazoline derivative (14), while reaction of (1) with formamide gave the N‐formylquinazoline derivative (15).

No abstract