CONTRIBUTION TO CINCHONA ALKALOIDS CHEMISTRY

Ph.D. Thesis Abstract Contribution to cinchona alkaloids chemistry
.
It appears that increasing the molar ratio QCD: TEA from 1:1 to 1:2 we obtain an increase
in efficiency of synthesis of the esters by about 30%. The same effect is observed with QCI
aminoalcohol. Experiments have shown that for a satisfactory performance it is necessary to carry
out the synthesis using reagents in the molar ratio QCD: BzCl: TEA 3:5:6.
There were synthesized the esters of 1,2-aminoalcohols with benzoic acid, salicylic acid
and acetylsalicylic acid. It was found that synthesis yields decrease for example from 83,8% for
benzoic acid ester to 64,76% for acetylsalicylic acid. Electron attractive substitutes grafted on the
benzene core decrease the reactivity of the acyl chloride. The decrease in synthesis efficiency can
be explained by the steric obstruction effect.
Newly synthesized compounds were characterized by H-NMR spectrometry, IR and
elemental analysis. The presence of 1768 cm-1 bands, 1393 cm-1 are characteristic to benzoate,
which proves the desired ester synthesis.
2.2.2. Synthesis of amides of 1,2 diamine QCDNH2
Amides of benzoic acid, salicylic acid and acetylsalicylic acid with diamine QCDNH2
were synthesized using chlorides of the acids as acylating agents for the amines (scheme 2.15).
Schema 2.15
COCl
+
N
THF, Et3N -HCl R
H2N 40
R
28 R = H 37 R = H
29 R = OH 38 R = OH
30 R= OCOCH 3 39 R = OCOCH 3
Synthesis of these amides is achieved with satisfactory yields 80.9% for benzoic
acid amide 37, 71.7% for salicylic acid amide 38 and 49% for acetylsalicylic acidamide 39. There
can be noticed the disable effect of electron attractive groups related to benzene nucleus on
this reaction, highlighted by the decrease the yield of synthesis.
20
O
NH
N