1.4- dibromo-2,3-butanedione

A wide range of amines can be used in the synthesis of these polymer-bound substrates, except for amines with nucleophilic side chains. This is due to the fact that 1,4-dibromo-2,3-butanedione is a strong alkylating agent. Amines with hydroxy functionalized side chains can be incorporated into the synthesis, whereas amines with tertiary amino groups in the side chain, for example N-(2-aminoethyl)morpholine, are not suitable due to byproduct formation. 

Among alkylating affinity labels, 8-[(4-bromo-2, 3-dioxobutyl)thio] ADP and -ATP (199 n = 2 or 3), formed by successive treatments of the corresponding 8-bromoadenosine phosphates with lithium hydrosulphide and 1, 4-dibromo-butanedione, have been used to label pyruvate kinase from rabbit muscle.355... 

The primary dihydro product (3) can be obtained by reduction of the quinoid (4). Compound 3, in which Ri = CeH= -CH= and Rj CgH can also be obtained by direct condensation of benzylidene selenosemicar-bazone with 2.3-dibromo-l,4-diphenyl-l,4-butanedione (Scheme 49). 

A. 1,3-Diacetylbicyclo[1.1.1]pentane (2). I1.1.1]Propellane is generated from 50 g (0.167 mol) of 1.1-dibromo-2,2-bis(chloromethyl)cyclopropane (Note 1) in pentane (Note 2) according to the procedure of Lynch and Dailey.3 To the solution of [1.1.1 Jpropellane, 1 (Note 3), is added 15 mL of freshly distilled 2,3-butanedione and the mixture is irradiated with a 450 W medium pressure UV lamp (Ace Glass Co, catalog no. 7825-34) at -10 5°C for 8 hr (Note 4). Solvents are evaporated on a rotary evaporator. The resulting crystalline material is washed three times with cold 2 1 pentane diethyl ether to give 16.95 g of 1,3-diacetylbicyclo[1.1.1]pentane (2) (Note 5). Another 1 g of the diketone is obtained upon concentration and crystallization of the pentane/diethyl ether rinses. Thus the total yield of 2 is 17.95 g [70% from 1,1-... 

In the first step, Rink amide AM PS Resin was acetoacetylated with diketene. Treatment with primary amines resulted in polymer-bound enaminones which then underwent a Hantzsch reaction [30] with l,4-dibromo-2,3-butanedione under formation of 5-(2-bro-moacetyl)pyrroles which could be cleaved from the resin with 20 % TFA/CH2C12. 

Bis(bromomethyl)quinoxaline (41), prepared by direct synthesis from o-phenylenediamine and l,4-dibromo-2,3-butanedione (BrCH2COCOCH2Br), can be similarly converted into the bispyridinium bromide 42, and this on treatment with p-nitroso-iV,N-dimethylaniline and sodium cyanide yields the biscyanoanil 44. Reaction with secondary amines such as diethylamine yields pyrroline derivatives (e.g., 43, see chapter XXXV). 

The reaction of l,4-dibromo-2,3-butanedione 78 with two moles of trimethyl phosphite produces the 2,3-diphosphate 79 via a double Perkow reaction.44... 

CeHi gBr i,Cu2N, 0(,, Dibromo (2,3-butanedione dioximato)copper (11) dimer, 44B, 910... 

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