Organophosphorus chemistry, 36[1]reactions of furobenzopyran-6-carboxaldehydes with alkyl phosphites and ylidenetriphenylphosphoranes [Witting reagents]

Dialkyl phosphites [4] and trialkyl phosphites [5] attack the aldehydic carbonyl carbon of 4-methoxy-5-oxo-5H-furo[3,2-g] benzopyran-6-carboxaldehyde [3a] and 4,9-dimethoxy-5-oxo-5H-furo [3,2-g] benzopyran-6- carboxaldehyde [3b] yielding the corresponding alpha-hydroxyphosphonates [7]. Compounds 7 regenerate the starting gamma-pyrone derivatives [3a or 3b] and the appropriate dialkyl phosphites [4] upon thermolysis under reduced pressure. On the other hand, the reaction of 3 with ylidenetriphenylphosphoranes [6] proceeds according to the Wittig mechanism to give the respective ethylenes [E 17]. The reaction of 3b with diethyl cyanomethylphosphonate [18] under Homer-Wittig conditions yields 6-[[alpha-cyano-alpha diethoxyphosphoryl] ethyliden-yl]-4,9-dimethoxy-5-oxo-5H-furo [3,2-g] benzopyran [20]. Structures of the isolated new products were elucidated by compatible, analytical, chemical and spectroscopic measurements

Synthesis of thiaphosphetane, thiadiphosphetane and thiazadiphosphetidine derivatives from the reaction of phosphacumulenes, phosphallene and phosphinimine with Lawesson's reagent

The active phosphacumulene ylides namely, N-phenylimino-[2], 2-oxo- [4] or 2-thioxo-vinylidenetriphenylphosphorane [6] are nucleophilic reagents which can be considered as versatile synthons for the synthesis of new heterocycles. They react with Lawesson's reagent [1] to give the corresponding thiaphosphetane derivatives 3, 5 and 7 respectively, which constitute an important class of heterocyclic compounds with medicinal and biological importance. On the other hand, Lawesson's reagent [1] can be converted by reaction with the active heteroallylic phosphonium ylide, hexaphenylcarbodiphosphorane [8], into the thiadiphosphetane 9. When the phosphinimine 10 reacts with Lawesson's reagent [1], the thiazadiphosphetidine 11 was obtained

Synthesis and reactions of 6-acetyl-7-hydroxy-4-methyl coumarin

Perkin condensation of 2, 4 diacetyl resorcinol with acetic anhydride and sodium acetate gave 6-acetyl-7-hydroxy-4-methyl coumarin [I]. Nitration of coumarin [I], then reduction followed by diazotization and coupling gave 3-azocoumarin derivative [V]. Alkylation of I followed by cyclization with anthranilic acid gave 2-[7/[6/acetyl-4-methyl] coumarinoxy] methyl-[4H] 3, 1-benzoxazin-4-one [VII]. The behavior of coumarin I towards bromination in different solvents, Claisen and Grignard reaction were studied and gave compounds [VIII-XII]. The structures of the products were confirmed by elemental analysis, IR and 1H-NMR spectroscopy

Hormonal treatments for induction of ovarian cyclicity in post-partum anoestrous barki ewes

At the beginning of the non-breeding season, 25 Barki ewes in their early postpartum period [21-28 days] were divided into 5 groups [5 ewes per group] and treated as follow: 1- Received no treatment [control], Norgestomet ear implant for 13 days plus 500 i.v. PMSG at the time of implant removal; 2- Progesterone releasing intravaginal sponge for 13 days; 3- Progesterone releasing intravaginal sponge plus 750 i.v. PMSG at sponge withdrawal; 4- 30 mg progesterone followed by ram introduction. Blood samples were collected at the end of treatment, during estrus and 10 days following estrus. Plasma progesterone was determined using RIA. In the 5 groups 0, 80, 0, 100 and 80% of ewes showed symptoms of estrus. The duration from the end of treatment to the onset of estrus was 78 +/- 6, 48 +/- 16.97, 144 +/- 24 hours in groups 2, 4 and 5, respectively. Plasma progesterone for the 5 groups were 0.351 +/- 0.105, 3.429 +/- 0.672, 2.2 +/- 0.72, 0.54 +/- 0.27 and 47.03 +/- 11.826 ng/ml at the end of treatment, 0.296 +/- 0.096, 0.597 +/- 0.096, 2.635 +/- 1.578, 0.097 +/- 0.04 and 0.314 +/- 0.06 ng/ml during estrus or expected day of estrus, 0.287 +/- 0.109, 1.874 +/- 0.283, 0.26 +/- 0.11, 3.68 +/- 0.08 and 2.738 +/- 0.903 ng/ml 10 days following estrus in the 5 groups, respectively. The data indicated that Norgestomet PMSG or progesterone releasing intravaginal sponge PMSG or progesterone priming followed by ram introduction could provide a beneficial method for induction of early ovarian cyclicity in early postpartum Barki ewes during the non-breeding season

Plasma estrogen and progesterone concentrations in relation to embryo yield in superovulated buffaloes

The relationships between plasma estradiol-17 beta and progesterone concentrations and each of the ovarian response and embryo yield were investigated in thirteen adult buffaloes. Superovulation was induced in these animals using FSH in combination with prostaglandin F2 alpha. Blood samples were collected daily for hormonal analysis from the day of treatment [day-4] to the day of embryo recovery [day 6 post-estrus]. The results revealed that 30.77% [G I] of the treated buffaloes did not respond to the superovulatory treatment [developed two or less copora lutea] whereas 69.23% [G II] responded to FSH-treatment by experiencing more than two corpora lutea. Progesterone [P[4]] concentration at the initiation of superovulation was higher [P < 0.01] in G II than in G I. This difference continued during all treatment days [days -4 to -1] and reappeared at day three post-estrus onwards. Estradiol-17B [E[2]] level differed significantly [P < 0.01] between the two groups on the day of estrus as well as one day before and after estrus. In G II, significant correlations existed between the number of recovered embryos and P[4] concentration at the initiation of superovulation, at estrus and on the day of embryo recovery. This revealed the P[4] level at the start of superovulation can be used as a reliable method to predict the embryo yield in buffalo species. E[2] concentration was correlated with the number of recovered embryos on the day of estrus and on the day of embryo collection. On the other hand, no correlations were found between P[4] or E[2] levels and the ovulation rate on the first day of treatment or on the day of embryo recovery. Hormonal profiles in buffaloes of G II showed marked changes in pre-and post-ovulation phase. However, in animals of G I no significant changes in hormone concentration were noted and this was considered a clear indication of the ovaries that are non-responsive to exogenous gonadotrophin