Palladium strontium carbonate

A more difficult problem is encountered when it is necessary to reduce selectively multiple bonds in the side chain, especially when they are conjugated with the nucleus. Up to the present time little has been published on this subject. The best method for the side chain reduction of /3-2-furylacrylic acid seems to be with Raney alloy in dilute NaOH. If the reaction is carried out more drastically, the nucleus undergoes easy reduction to give 4-hydroxy-valerolactone. The method of Railings and Smith also appears to be successful this involves the use of palladium strontium carbonate for the reduction of the alkene side chain of 2 -furylalkenes, without affecting the ring. Such compounds as j8-2 -furylacrylic esters are exceptions, but the potassium salt of the acid can be selectively reduced in aqueous solution. 

Palladium-strontium carbonate Hydrogenation of ethylene derivatives... 

Palladium-strontium carbonate Selective and partial hydrogenation of carbon-carbon double bonds... 

Palladium-strontium carbonate sodium hydroxide Replacement of bromine by hydrogen s. 21, 400... 

Palladium-calcium carbonate/quinoline Hydrogenation of acetylene derivatives partial and selective s. 16, 80 Palladium-strontium carbonate Partial ring hydrogenation of isocyclics s. 17, 89... 

Palladium-strontium carbonate/oxalic acid Hydrocarbons from tert. amines s. 11,133... 

Palladium-strontium carbonate Cyclohexanone from 2-cyclohexenone ring... 

Palladium-strontium carbonate Dimerization of halides with formation of inner complex salts Pyrrole derivatives... 

The palladized strontium carbonate is prepared as follows. Suspend 33 g. of strontium carbonate in 350 ml. of water at 70°. Add 2 g. of palladium chloride dissolved in 10 ml. of concentrated hydrochloric acid, and stir the mixture at 70° for 15 minutes. Filter the mixture, wash the product thoroughly with hot water, and dry the product at 110°. 

Palladium catalysts resemble closely the platinum catalysts. Palladium oxide (PdO) is prepared from palladium chloride and sodium nitrate by fusion at 575-600° [29,30]. Elemental palladium is obtained by reduction of palladium chloride with sodium borohydride [27, 31], Supported palladium catalysts are prepared with the contents of 5% or 10% of palladium on charcoal, calcium carbonate and barium sulfate [32], Sometimes a special support can increase the selectivity of palladium. Palladium on strontium carbonate (2%) was successfully used for reduction of just y, (5-double bond in a system of oc, / , y, (5-unsaturated ketone [ii]. 

The y, -double bond of a linear dienone is selectively reduced over palladium in the presence of a trace of base.15,62,85,86,137 Presaturation of the catalyst with hydrogen enhances the selectivity in the reaction.137 In the absence of base, the use of strontium carbonate or barium sulfate as a support for the palladium is preferred.56,57 A benzene solvent is also beneficial.78... 

Concerning the structure of pseudomorphine little is known with certainty. The two morphine units were originally believed to be joined in the 2 2 positions as this was assumed to be the reactive position in the morphine molecule [i], and bromomorphine, believed to have the bromine in position 2, cannot be oxidized in this way [47]. However, the bromine atom in bromomorphine is now known to be in position 1 [48], which is presumably the most reactive position, and pseudomorphine may be 1 l -dimorphine. An attempt to reduce 1-bromomorphine to a dimolecular derivative by heating in alcoholic alkali with palladium on strontium carbonate and hydrazine (method of Busch [49]) failed, only amorphous coloured substances being obtained [50]. 

Several 7-bromopyrido[2,3-/ ]pyrazines 4 have been dehalogenated by hydrogenolysis in the presence of palladium on strontium carbonate.18... 

Under the above reaction conditions the A8 double bond in 3 remains intact. This benzylic double bond can be reduced over palladium hydroxide on strontium carbonate. Likewise, hydrogenation of trans (A/B ringj-fused unsaturated ketone 5 viclds the trans-anti-cis ketone... 

Raney iron and palladium on strontium carbonate also have been used as catalysts in reducing certain acetylenes to olefins. 

The synthesis of lupeol starts with the cyclization of 6-methoxy-p-methyl-a-tetralone 28 with 4-7V 7V -dimethylamino-2-butanone methiodide in the presence of potassium /-butanolate to l,9,10,10a-tetrahydro-7-methoxy-3(2//)-phenanthrone 27. Reduction with sodium borohydride and subsequent hydrogenation of the enone CC double bond in the presence of palladium and strontium carbonate as slightly deactivated catalyst gives the oetahydrophenanthrol 26. Partial reduction of the benzenoid ring to the enone is aceomplished by lithium in liquid ammonia. The enone is derivatized to the benzoate 25 in order to protect the hydroxy group prior to the subsequent synthetic steps. 

Reliable Sample for Radiation Detection. The sample must be prepared for counting by an effective method. Many such methods have been published, each appropriate for its element. For example, strontium may be prepared for counting as strontium oxalate or carbonate, and iodine as silver or palladium iodide. Samples submitted for mass spectrometric analysis must be in a form that is suitably volatilized and processed by the instrument. 

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