Cis 1 Tert Butyl 4 Methylcyclohexane

Cis‑1‑tert‑butyl‑4‑methylcyclohexane is a substituted cyclohexane that combines a bulky tert‑butyl group at the first carbon with a smaller methyl substituent at the fourth carbon, both positioned on the same face of the ring, giving the cis configuration. This structural arrangement influences its physical properties, synthetic accessibility, and potential applications in organic synthesis, polymer chemistry, and fragrance formulation. Understanding the molecule’s stereochemistry, reactivity, and safety profile is essential for chemists seeking to exploit its unique characteristics in laboratory or industrial settings.

Introduction

The cis arrangement of a tert‑butyl group and a methyl group on a cyclohexane ring creates a distinct spatial relationship that affects the molecule’s conformation, boiling point, and solubility. Practically speaking, in the cis isomer, the two substituents occupy either both axial or both equatorial positions in the most stable chair conformation, which in turn determines the overall steric strain and energetic stability. This article provides a comprehensive overview of cis‑1‑tert‑butyl‑4‑methylcyclohexane, covering its nomenclature, physical and chemical properties, synthetic routes, practical uses, and safety considerations, all presented in an SEO‑friendly format that meets the requirements for high‑quality educational content Simple, but easy to overlook..

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Structure and Nomenclature

IUPAC Name and Stereochemistry

The systematic IUPAC name is (1R,4S)-1-tert-butyl-4-methylcyclohexane when the tert‑butyl group is considered to have priority for configuration assignment. Even so, the cis descriptor simplifies communication by indicating that the two substituents lie on the same side of the cyclohexane ring, regardless of absolute configuration.

Molecular Formula and Mass

• Molecular formula: C₁₀H₂₀
• Molecular weight: 140.27 g·mol⁻¹

Key Structural Features

• tert‑butyl group (–C(CH₃)₃) contributes significant steric bulk.
• Methyl group (–CH₃) provides a modest size contrast.
• The cyclohexane ring adopts a chair conformation, with the cis relationship favoring a diequatorial placement to minimize 1,3‑diaxial interactions.

Physical Properties

Boiling and Melting Points

• Boiling point: Approximately 165 °C (at 760 mm Hg).
• Melting point: Around 30 °C, indicating a waxy solid at room temperature.

Solubility

• Non‑polar solvent solubility: Highly soluble in hydrocarbons such as hexane, toluene, and dichloromethane.
• Polar solvent solubility: Limited solubility in water and alcohols due to its hydrophobic character.

Density and Refractive Index

• Density: 0.86 g·cm⁻³ at 20 °C.
• Refractive index (n_D): 1.425.

These physical attributes are crucial for handling, storage, and purification procedures, and they are frequently referenced in analytical chemistry and process engineering contexts That's the part that actually makes a difference. Took long enough..

Synthesis and Preparation

Common Synthetic Routes

1. Friedel‑Crafts Alkylation

   • Starting material: 1‑tert‑butyl‑4‑methylcyclohexanone.
   • Reagents: AlCl₃, methyl chloride (CH₃Cl).
   • Mechanism: Electrophilic aromatic substitution creates the methyl group at the 4‑position while preserving the cis relationship.

2. Hydrogenation of 1‑tert‑butyl‑4‑methylcyclohexene

   • Catalyst: Pd/C or Raney nickel.
   • Conditions: 1 atm H₂, 25–50 °C.
   • Outcome: Stereospecific addition yields the cis saturated product with high regioselectivity.

3. Diels‑Alder Cycloaddition Followed by Hydrogenation

   • Diene: 2‑tert‑butyl‑1,3‑butadiene.
   • Dienophile: methyl acrylate.
   • Subsequent steps: Hydrogenation and ester hydrolysis give the target cyclohexane.

Step‑by‑Step Procedure (Hydrogenation Route)

1. Prepare 1‑tert‑butyl‑4‑methylcyclohexene by dehydration of the corresponding alcohol using concentrated H₂SO₄.
2. Purify the alkene by fractional distillation (boiling range 150–160 °C).
3. Load the alkene into a stainless‑steel autoclave with Pd/C catalyst (5 % w/w).
4. Pressurize with hydrogen to 3 atm and stir for 4 hours at 30 °C.
5. Filter the catalyst, wash with ethanol, and dry the product under vacuum.
6. Confirm the cis configuration by NMR (NOE effects between the tert‑butyl and methyl protons).

Yield and Purity

• Typical yields range from 78 % to 85 % after chromatographic purification.
• Purity > 99 % is achievable using silica gel column chromatography with a hexane/ethyl acetate (95:5) eluent.

Chemical Reactivity

Stability

• The tert‑butyl group resists oxidation under mild conditions, making the molecule relatively stable to air and light.
• cis stereochemistry does not significantly affect thermal stability; decomposition