Chapter 1 Effect of Substituted in Organic molecule
1. 试判断下列各对基团,那一个具有强的-I效应(即强的吸电子诱导效应):
-
(1) -COOH , -COO
HNCOCH3 , COCH3 , SO2H ,
(2) (3) (4) (5) (6) (7) (8) (9)
H+NCN(CH3)2CH3 CCH2CH3, SO3H
OCH3 , CCCH3HH ,
SCH3 CCCH3
N(CH3)2 , Si(CH3)3 ,
+N(CH3)3 ,
P(CH3)2 Si(CH3)2CH3
NH2 CH2NH2 Cl CCCH3HH
(10) CN ,
(11) SiCH3 , (12) (13)
CCCH3 ,
,
(14)
O2SNO2CH3 ,
O2SNO2
Br(15) ,
2. 指出下列各对酸中哪一个酸性强
(1) H3NCH2CH2COOH , HOCH2CH2COOH (2) HCCCOOH ,
H2CCCOOHH
CH3CH3COO(3) C6H5COCH2COOH , C6H5CHOHCH2COOH
nC4H9CHHOOCCCCOO(4) COOH ,
CH3CH3
OH(5) (6) BrCH2(7)
OHCOOH
, COOH
CH2COOH , CH3CHBrCOOH
CHCOOH
(H3C)2CH2 ,
H2CCHCH2COOH
COOH(8) HCCCOOH , SHOOCHC
COOCl(9) CH2(COOH)2 ,
(10) CH3OCH2CH2COOH , CH3SCH2CH2COOH (11) CH3SCH2COOH ,CH3SO2COOH
COOHCOOH(12)
OHC ,
CHO
OHOH(H3C)3CC(CH3)3(H3C)3CC(CH3)3CH3(13)
H3CO,
OCH3
(14) COOH ,
H3CCOOH
SeH(15) C6H5CH2SeH ,
3. 预料以下各对化合物,何者具有更强的酸性? (1) CH3NO2 ,(CH3)2CHNO2
(2) CH2(SO2C6H5)2 ,CH2(SOC6H5)2
(3) ,(C6H5)2CHCH2C6H5 (4) CH3COCH2COOCH3 ,CH3COCH2CONH2 (5) CH3COCH2COCH2F ,CH3COCHFCOCH3
OCH3H3CONH3CCH(C6H5)2(6)
N ,
O(7)
O2SSO2O ,
H3C
NO2CH3NO2H3CCH3CH3(8) ,
CHCH3
CH(9)
CH(C6H5)23 ,
3
CH(C6H5)2(10) ,
(11) (CH)3Se , (CH3)2O
(12) ,
4. 解释以下现象:
(1). 杯烯 (Calcene) 的偶极距很大,? = 5.6 D.
(2). 吡咯 ? = 1.80 D,吡啶 ? = 2.25 D,且极性相反,如图:
NHN
5. 比较下列化合物的碱性的强弱:
N(CH3)2NN(C2H5)2NNH2
6. 9,10-二氢蒽-1-羧酸(A)和9,10-乙撑蒽-1-羧酸(B)的酸性取决于8-位上取代基X
的性质。
XCOOHXCOOH (A) (B)
X pKa(A) pKa(B)
-H 5.6 5.98 -OCH3 - 6.15 -Cl 5.71 6.24 -CO2 6.31 6.89
(1) 说明(A)、(B)中pKa值按H,OCH3,Cl和CO2依次排列 (2) 为什么(A)的酸性比对应的(B)酸大一些,(横看pKa(A)比pKa(B)小)。
7. 按Pka的大小排列下列化合物:
O(1).CH3CHCOO-+NH3CH3CHCNH2+NH3(2).OHNNHOOHNNHO(3).O(4).H2COCHCH2OCHOCH2OOCH3CCH2CH2CCH3COOHCH3CCH2CCH2CH3COOHOHCH3CCH2COCH2CH3COOHHONH3+(5).(6).NH3O2NCH2OH+NH3+CH2COOHOHOH(7).NO28. 比较下列化合物的酸性大小:
OCH3CCH3OCH3SCH3OOCH3NO2CH3CPhCH3CN
+++9. 按诱导效应的强弱次序排列下列基团:
OR
OR2+ClSRNR3SR2TeR2AsR2

