Tetramethyl ethylenediamine

A kind of modification of the Polonovski-Boon synthesis is the reaction of 5,6-dihalopyrimidines with ethylenediamine derivatives. Depending on the bulkiness of the amino substituents a more or less regiospecific condensation may proceed (71CB780), as shown recently in the reaction of 5-bromo-6-chloro-l,3-dimethyluracil (279) with 2-methyl-amino- -propylamine to form l,3,5,6-tetramethyl-5,6,7,8-tetrahydrolumazine (280 equation 99) (80Ba3385). 

In general the chiral additive (l/ ,2/J)-l,2-dimethoxy-l,2-diphenylethane was the most effective while (.S )-2.2 -diniethoxy-1,1 -binaphthalene and (1 / ,27 )-/V,/V,/V, A"-tetramethyl-1,2-diphcnyl-ethylenediamine induced only very low levels of enantiofacial differentiation. In the case of the acyclic enimines competing 1,2-addition products were also obtained7. 

Fig. 24a and b. Differential molecular weight distribution curves of polyisoprene prepared, a) with oligoisoprenyl-Li b) with oligoisoprenyl-Li in the presence of NNN N tetramethyl ethylenediamine [TMDA]/[OLi] = 0.01) (A. Davidjan, N. N. Lolaev, V. Sgonnik, B. Belenkii, V. Nesterov, B. Erus-salimsky, Ref. 1531... 

Polyacrylamide gel is the most commonly used type of support medium for gel electrophoresis, and polyacrylamide gel electrophoresis is simply known as PAGE. The gel is usually formed by polymerization of acrylamide and the cross-linking agent N, iV -methylene-bis-acrylamide (Bis) in the presence of ammonium persulfate (APS, initiator) and N, N, N, iV -tetramethyl-ethylenediamine (TEMED, accelerator). The total concentration of acrylamide... 

In 1985, Kwiatkowski et al. reported a tetramethyl ethylenediamine (TMEDA)-catalyzed dimerization of ketene giving the interesting compound 4-methylene-oxetane-2-one (diketene). This substance can be hydrogenated by either Pd/C to racemic p-BL as well as by asymmetric catalysis according to Takaya et al. using Ru complexes of (5)-BINAP as catalyst, with an ee of 92% [111] (Fig. 39). 

The influence of two tertiary polyamines on the a-nionic polymerization of isoprene in cyclohexane has been studied. TMEDA (N,N,N, N -tetramethyl-ethylenediamine) and PMDT (pentamethyIdiethylene-triamine) can increase or decrease the propagation rate, depending on the concentration range. The results are discussed on the basis of the nature of the living species. 

Metal chelates contain 1 1 molar ratio of ligand to metal ion. TMEN = tetramethyl-ethylenediamine DMEN = dimethylethylenediamine DIPY = a,a -bipyridine PHEN = o-phenanthroline HEN = iV-hydroxyethylethylenediamine DHEN = JV ,iV /-dihy-droxyethylethylenediamine. 

A series of complexes of the type ML(SCN) (C104)2-, (M - Zn, Cd, or Hg x = 1 or 2) has been prepared where L is en and its tetramethyl derivative, diethylenetriamine and its pentamethyl derivative, triethylenetetramine and its hexamethyl derivative, and bis(ethylenediamine). The complexes are either monomeric with four-, five- or six-coordinate metal, or polymeric containing bridging thiocyanate the perchlorate is always ionic. The thiocyanate is generally bonded through nitrogen to zinc and cadmium (and through sulfur to mercury).181... 

The deuteriated (97%) imines 363 and 365, and the hydrazone 364 have been prepared396-399 by treating 2,6,6-trideuterio-2-methylcyclohexanone and 2,2,6,6-tetradeuteriocyclohexanone with the corresponding deuteriated ammonium salts (RND3CI) and used in the KIE studies of the metalation of the above C=N compounds with lithium diisopropylamide (LDA) in THF, in N, N, N A -tetramethyl ethylenediamine (TMEDA) and in dimethylethylamine (DMEA) solvents (equation 200). The rates, d[imine]/dt of that of imines 363 and 364 metalation are zero order with respect to [THF], [TMEDA]... 

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