Mitsunobu reactions with methanesulfonic acid; The replacement of equatorial hydroxyl groups by azide with net retention of configuration

Diversity Oriented One‐Pot Synthesis of Complex Macrocycles: Very Large Steroid–Peptoid Hybrids from Multiple Multicomponent Reactions Including Bifunctional Building Blocks

“…Scheme summarizes the synthesis of the steroidal bifunctional building blocks from lithocholic acid ( 2 ). Synthesis of diamine 3 and diisonitrile 6 proceeded by a double Mitsunobu reaction to the corresponding reduced acid, followed by azide displacement,12a reduction, and subsequent isonitrile formation 12b. Steroidal dicarboxylic acids are a source of additional skeletal diversity.…”

CuAAC Synthesis and Anion Binding Properties of Bile Acid Derived Tripodal Ligands

“…[39] Amides 2a-2c were Bile azides 3a-3c and 4 were synthesized by using a standard route by nucleophilic substitution of the corresponding α-and β-mesylates with sodium azide in dimethyl sulfoxide (DMSO; Scheme 2). [22,40] A previously reported synthesis of 24-azidocholane derivatives relied upon the rather unselective mesylation of 3,24-cholanediols (75:25 ratio for mono/dimesylate). [41] To avoid a tedious separation of mono-and dimesylates the 3-OH was protected with a trityl group.…”

Synthesis of Novel Steroid-Peptoid Hybrid Macrocycles by Multiple Multicomponent Macrocyclizations Including Bifunctional Building Blocks (MiBs)

“…As depicted in Scheme 4 (top), an unidirectional Ugi-MiB approach can be implemented easily by utilizing the lithocholic acid derivative 17 functionalized with an amino group at C-3. This compound was readily prepared from methyl lithocholate according to reported procedures [13,24]. The 3α-OH is replaced by an azido group with retention of configuration, followed by ester hydrolysis and azide reduction.…”