σ ₁ and σ₂ receptor affinity of the spirocyclic cyclohexanes with an amino moiety in the 3′-position and reference compounds.

Compd.	NR2	Distancea (Å)	K i ± SEM [nM]
			σ 1	σ 2
1 (ref. 32)	—	5.6 - 5.7 Å 5.1–5.2 Å	0.69 ± 0.17	99.7 ± 19.8
trans-3a (ref. 40)	NHCH2C6H5	6.0–6.3 Å 6.5–6.6 Å,	256 ± 72	13%c
cis-3a (ref. 40)	NHCH2C6H5	7.2 Å 6.3 Å	97 ± 4.8	503b
trans-3b (ref. 40)	NHCH2C6H11	6.0–6.3 Å 6.5–6.6	15 ± 2.6	99 ± 17
cis-3b (ref. 40)	NHCH2C6H11	7.2 Å 6.3 Å	18 ± 3.8	84 ± 19
cis-4a	NHCH2C6H5	5.9–6.1 Å	95 ± 35	340b
cis-4b	NHCH2C6H11	5.9–6.1 Å	5.4 ± 2.8	60 ± 40
cis-5a	N(CH3)CH2C6H5	5.5–5,7 Å	278 ± 2	24%c
cis-5b	N(CH3)CH2C6H11	5.5–5.7 Å	15 ± 4.6	34%c
(+)-pentazocine			5.4 ± 0.5	—
di-o-Tolylguanidine			71 ± 8	54 ± 8

^aDistance refers to the distance between the center of the benzene ring of the 2-benzopyran and the N-atom; the value in the first line defines the distance, when the benzene ring of the 2-benzopyran adopts the equatorial orientation at the cyclohexane ring and the second value describes the distance for the axial orientation of the benzene ring.

^bResult from one measurement.

^cInhibition of radioligand binding (%) at a test compound concentration of 1 μM.