2444-101911

2444-101911 - 1 Reactions EtSH , cat. BF3 SEt CHO SEt CHO S

Info iconThis preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
Reactions 1 CHO CHO O O EtSH , cat. BF 3 1,3-propanedithiol Me 2 CHSH 1,2-ethanedithiol BF 3 BF 3 BF 3 SEt SEt S S Me 2 HCS SCHMe 2 S S
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Dithioacetals and Dithioketals: Hydrolysis 2 • Dithioacetals and dithioketals can be converted back to the carbonyl under acidic conditions in the presence of an excess of water, because every step is reversible (just as with acetals and ketals). • Aqueous hydrolysis is more difficult for dithio- derivatives when compared to acetals or ketals, and water-compatible Lewis acids such as mercuric (Hg +2 ) salts are used. • Dithioacetal 68 , for example, is converted back to benzaldehyde ( 67 ) when it is treated with HgCl 2 (mercuric chloride) and BF 3 (boron trifluoride), in aqueous ether. • Similar treatment of 66 gives 23 . S S CHO 68 67 O SC 3 H 7 SC 3 H 7 66 23 HgCl 2 , BF 3 H 2 O/ether
Background image of page 2
Reactions 3 OCH 3 OCH 3 O O SCH 3 SCH 3 S S H 2 O cat. H 2 SO 4 aq. H + HgCl 2 , BF 3 HgCl 2 , BF 3 O + 2 MeOH O + 2 MeSH O OH HO + O SH HS +
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Reaction with Amines 4 • Amines have the structure 71 . If 71 has three alkyl groups it is a tertiary amine. With two alkyl groups and one hydrogen atom it is a secondary amine, and when 71 has one alkyl group and two hydrogen atoms it is a primary amine. • Two important nitrogen-containing compounds are an imine ( 72 ) that is characterized by a C=N unit and an enamine ( 73 ) that is characterized by a C=C-N unit. • Reaction of an aldehyde or ketone with a primary amine gives an imine ( 72 ), but secondary amines react to give an enamine ( 73 ). N R R 2 R 1 R 1 N R 2 R R 72 73 N R R R 71
Background image of page 4
Reaction with Primary Amines 5 • If a primary amine such as (1-methylethyl)amine (called, isopropylamine, Me 2 CHNH 2 ) reacts with acetone ( 6 ), acyl addition leads to an ammonium salt ( 74 ).
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 17

2444-101911 - 1 Reactions EtSH , cat. BF3 SEt CHO SEt CHO S

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online