(1R,2R)-(-)-1,2-Diaminocyclohexane
[CAS# 20439-47-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Polyamine
• Name: (1R,2R)-(-)-1,2-Diaminocyclohexane
• Synonyms: (R,R)-DACH
• Molecular Formula: C₆H₁₄N₂
• Molecular Weight: 114.19
• CAS Registry Number: 20439-47-8
• EC Number: 606-556-6
• SMILES: C1CC[C@H]([C@@H](C1)N)N

Properties

• Density: 0.9±0.1 g/cm³ Calc.^*, 0.954 g/mL (Expl.)
• Melting point: 40-45 ºC (Expl.)
• Boiling point: 193.6 ºC 760 mmHg (Calc.)^*, 220.9 - 222.2 ºC (Expl.)
• Flash point: 75.0 ºC (Calc.)^*, 70 ºC (Expl.)
• Index of refraction: 1.484 (Calc.)^*, 1.49 (Expl.)
• Alpha: -24.5 º (c=5, 1 n hcl) (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS07 Danger
• Hazard Statements: H314-H317
• Precautionary Statements: P260-P261-P264-P272-P280-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P321-P333+P317-P362+P364-P363-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin corrosion	Skin Corr.	1B	H314
Skin sensitization	Skin Sens.	1	H317
Serious eye damage	Eye Dam.	1	H318
Skin corrosion	Skin Corr.	1C	H314

• Transport Information: UN 3259

Discovory and Applicatios

(1R,2R)-(−)-1,2-Diaminocyclohexane is the enantiomerically pure form of 1,2-diaminocyclohexane, featuring two amino groups positioned on adjacent carbons of a cyclohexane ring in a cis configuration. The (1R,2R) stereochemistry denotes the absolute configuration of the two chiral centers, and the (−) sign indicates that this is the levorotatory enantiomer, meaning it rotates plane-polarized light counterclockwise.

This compound is widely used as a chiral ligand and building block in asymmetric synthesis due to its bidentate coordination ability through the two amino groups. The cis arrangement allows it to chelate metal centers effectively, making it valuable in the preparation of metal complexes that serve as catalysts in enantioselective transformations such as hydrogenation, allylic substitution, and cyclopropanation.

The synthesis of enantiomerically pure (1R,2R)-1,2-diaminocyclohexane can be accomplished by resolution of the racemic mixture through diastereomeric salt formation or by asymmetric synthesis methods starting from chiral precursors. Its availability in optically pure form is crucial for applications requiring high enantioselectivity.

In coordination chemistry, (1R,2R)-(−)-1,2-diaminocyclohexane forms stable chelate complexes with transition metals like platinum, rhodium, and ruthenium. These complexes are extensively studied and employed as catalysts in pharmaceutical and fine chemical manufacturing. The rigidity of the cyclohexane ring combined with the stereochemical arrangement provides well-defined chiral environments for catalytic reactions.

Apart from catalysis, derivatives of this diamine are also investigated in medicinal chemistry for their potential biological activities. Metal complexes bearing this ligand have shown promise as antitumor agents and in other therapeutic contexts.

Physically, (1R,2R)-(−)-1,2-diaminocyclohexane is a colorless to pale yellow liquid or crystalline solid, depending on purity and conditions. It is soluble in water and polar organic solvents due to the presence of two primary amine groups, which also contribute to its basicity and reactivity.

Overall, (1R,2R)-(−)-1,2-diaminocyclohexane is a valuable chiral diamine with significant roles in asymmetric catalysis, coordination chemistry, and potential biomedical applications, owing to its defined stereochemistry and coordination capabilities.

References

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DOI: 10.1186/1471-2407-7-65

2023. The synthesis of bi(poly)- and macrocyclic derivatives of trans-diaminocyclohexane (microreview). Chemistry of Heterocyclic Compounds, 59(11).
DOI: 10.1007/s10593-023-03246-3

2023. Asymmetric organocatalysis: from a breakthrough methodology to sustainable catalysts and processes. Russian Chemical Bulletin, 72(1).
DOI: 10.1007/s11172-023-3713-5