Diazomethane, reaction with hydrogen over

Esters of racemic pyrazolidine-3-carboxylic acid (5-azaproline, 16) are obtained by a two-step reaction via addition of diazomethane to acrylic acid esters to form the corresponding dihydropyrazoline derivatives, which are converted into the desired pyrazolidine-3-carb-oxylic acid derivative by hydrogenation over palladium on charcoal,11621 or by reduction with sodium cyanoborohydride,[164l or with zinc in acetic acid. Details are given in Table 6J1651... 

The other example to be discussed in this context comes from Pettit s group. Simultaneous treatment of the iron complex (/u.-CH2)[Fe(CO)4]2 (35) with hydrogen and ethylene gives both methane (66%) and propylene (6%), the expected products from the two separate reactions. In addition, ethane (—600%) is formed, with the actual hydrogenation catalyst still to be determined (72). Because simple diazoalkanes provide the cleanest method to metal-attached alkylidenes, and with the expectation that dissociative chemisorption of diazomethane to absorbed CH2 and free N2 would occur, the reactions of CH2N2 with and without H2 over various transition metals were examined in a careful study with regard to the product ratio (73). It was found, that gas-phase decomposition of the parent diazoalkane upon passage over active Ni, Pd, Fe, Co, Ru, or Cu-... 

Aryl diazomethanes and ethyl diazoacetate lose nitrogen completely when hydrogenated over palladium in neutral medium at room temperature and atmospheric pressure. Aryl diazoketones, however, under the same conditions, give the a-amino ketones which condense directly to the dihydropyrazines. The addition of acetic acid to the solvent for this later reaction permits the isolation of the amino ketone (Eqn. 19.32). With dilute hydrochlorie acid in the reaction mixture, complete loss of the nitrogen was observed. The hydrogenation of alkyl diazoketones in neutral or acetic acid solution results in hydrazone formation (Eqn. 19.33). ... 

Heat 3-nitrophthalic anhydride with ammonium carbonate to get 3-nitrophthalimide (I). Dissolve 4.3 g (I) in 50 ml 90% methanol and add 1.9 g sodium borohydride over 30 minutes while stirring vigorously at room temperature. Stir 2 hours, acidify with 20% HCI, evaporate in vacuum and treat the dry residue with acetone. Evaporate in vacuum to get 3.9 g (88%) 3-OH-4-nitrophthal-imidine (II) (recrystallize from acetone). Dissolve 3.9 g (II) in 40 ml 20% HCI and stir for 10 hours on water bath at 80-90°. Distill off HCI and stir residue with acetone. Filter and evaporate in vacuum to get 3.4 g 3-OH-4-nitrophthalide (III) (recrystallize from CHC 3 and can purify on column). Prepare an ether solution of CH2N2 and add to 1.93 g (III) in a 100 ml flask until a reaction is no longer evident. Add acetic acid to decompose excess diazomethane and evaporate in vacuum to get about 2 g of 2-methoxycarbonyl-6-nitrostyrene oxide (IV) (can purify on column). Dissolve 560 mg (IV) in 50 ml absolute methanol, add 50 mg Pt02 and hydrogenate as described elsewhere here (other reducing methods should work). Filter,... 

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